Have $2,500 too spend.
Drifting
Joined: Jun 2010
Posts: 1,349
Likes: 3
From: US
Nitrous can be just as reliable as any other type of F/I as long as it is setup correctly and the tune is good. The only times people really run into issues with nitrous is when they get greedy and spray to much or the tune is not setup right. If you are on a budget for money and really want a go fast mod - then Nitrous would be an awesome choice. Hell - a Cam, Valvetrain, LS6 Intake manifold, plus a nice little 100 shot of nitrous would be pretty damn strong. 
Race Director
Joined: Apr 2005
Posts: 11,138
Likes: 11
From: Fremont CA
St. Jude Donor '06-'07-'08-'09-'10-'11-'12-'13-'14-'15-'16-'17-'18-'19-'20
NCM Sinkhole Donor
Not a bad idea, minimal gains with stock heads/cam.
Again, minimal gains, add the intake manifold and your over $500 for +1 WHP gain.
For a street car this is a complete waste.
Will cost more than that and yet again, something that will not yield any noticeable gains.
It's been proven that a smoother coupler does not offer any gains, do a search, power ducts do not increase power.
They are, but a waste of time and $ IMO.
Now we're talking...
To the OP;
Do your self a favor and get a good tune done, shouldn't run you over $400 for a quality dyno tune that will offer a great value in performance and drive-ability upgrades. If you can work on your car your self you can pick up a nice cam kit, get a dyno tune and be over 400 WHP.
Don't worry about the intake manifold and throttle body unless you are going to do head and cam work. At that point you'll be better off going to a FAST intake as well as a LS2 TB.
Also consider doing some supporting mods to help you yield the most value out of your tune like a lower temp thermostat and have the fans adjusted to come on earlier.
Again, minimal gains, add the intake manifold and your over $500 for +1 WHP gain.
For a street car this is a complete waste.
Will cost more than that and yet again, something that will not yield any noticeable gains.
It's been proven that a smoother coupler does not offer any gains, do a search, power ducts do not increase power.
They are, but a waste of time and $ IMO.
Now we're talking...
To the OP;
Do your self a favor and get a good tune done, shouldn't run you over $400 for a quality dyno tune that will offer a great value in performance and drive-ability upgrades. If you can work on your car your self you can pick up a nice cam kit, get a dyno tune and be over 400 WHP.
Don't worry about the intake manifold and throttle body unless you are going to do head and cam work. At that point you'll be better off going to a FAST intake as well as a LS2 TB.
Also consider doing some supporting mods to help you yield the most value out of your tune like a lower temp thermostat and have the fans adjusted to come on earlier.
All a waste of money on a street car with a stock motor.If "go fast" means off-the-line acceleration, then change to a 3:42 or 3:73 rear-end.
But if "go fast" means more engine power, then a cam and heads (bought used from a forum member) and a tune.
And if go fast means all of the above, then put a second mortgage on the house and then shoot the moon: cam, heads, blower and gears. That ought to set you back about $15k.
The Lizzard
But if "go fast" means more engine power, then a cam and heads (bought used from a forum member) and a tune.
And if go fast means all of the above, then put a second mortgage on the house and then shoot the moon: cam, heads, blower and gears. That ought to set you back about $15k.
The Lizzard
Gears are your best bang for the buck. However, the OP has a Z06, so he already has 3.42 gears. 3.73 will be an improvement, but 3.90 will really be felt more. Gears are directly proportional to power to the ground.If you have 3.42 now,....
3.73 = 9% increase in power to the ground
3.90 = 14% increase in power to the ground
4.10 = 20% increase in power to the ground
So, let's say you have 405 hp (flywheel) now, adding 3.90 gears would be like adding 57 hp at the flywheel. That is power you can really feel.
There ARE downsides to gears. Higher RPM's at cruising speeds. That means more engine wear, more engine noise, and decreased gas mileage. Less top speed (but who really drives their car 180mph?)
GEARS
Race Director
Joined: Apr 2005
Posts: 11,138
Likes: 11
From: Fremont CA
St. Jude Donor '06-'07-'08-'09-'10-'11-'12-'13-'14-'15-'16-'17-'18-'19-'20
NCM Sinkhole Donor
It should also be noted that the LS6 is the most reliable motor that GM has ever built. Generally good for 300,000 miles **IF** you don't touch the motor. As soon as you open it up, all bets are off. I would stay away from heads and cams if I were you.
Drifting
Joined: Jun 2010
Posts: 1,349
Likes: 3
From: US
100-125 shot of nitrous and tune
Cam, Valvetrain, etc
OR
Both
These options are within your budget and can really liven up the ride. It all comes down to what you want.
Race Director
Joined: Apr 2005
Posts: 11,138
Likes: 11
From: Fremont CA
St. Jude Donor '06-'07-'08-'09-'10-'11-'12-'13-'14-'15-'16-'17-'18-'19-'20
NCM Sinkhole Donor
The OP is actually inquiring about a 99 C5 Coupe. But still the same concept applies. The LS1 is very reliable as well. Of course if you want to go fast then you'll have to sacrifice but that is the name of the game.
100-125 shot of nitrous and tune
Cam, Valvetrain, etc
OR
Both
These options are within your budget and can really liven up the ride. It all comes down to what you want.
100-125 shot of nitrous and tune
Cam, Valvetrain, etc
OR
Both
These options are within your budget and can really liven up the ride. It all comes down to what you want.
Either way, for reliability just change the gears and leave the engine alone.
Burning Brakes
Joined: Jul 2010
Posts: 835
Likes: 4
From: Los Angeles CA
This was one of the main reasons that I bought a C5. It's easy to mod and I didn't need to pour tons of money into the motor to get it to where I wanted it to be. So far I have invested around 6000 into the car. If I was to want to sell tomorrow, I could have every mod taken off and replaced with the stock part with only a few weekends of work. Only parts I bought new were coilovers and intake. Wheels, brake kit, control arms, handheld tuner, racing seats, headers, exhaust, etc... were all bought used and could be resold for practically the same price.
That being said, the power bug is starting to bite, and I think the only way to thwart it off is to start seriously tracking my car and spending all my money on consumables and cooling upgrades.
Burning Brakes
Joined: Feb 2008
Posts: 949
Likes: 1
From: Tampa fl
St. Jude Donor '14
down payment on a new one!!! 
otherwise... the above are some good bolt on mods, some of those htings you can get for cheaper like a catch can from corvettemods.com is much cheaper and a good design. Some tuning shops will do a TB port for $100, or you can do it yourself for cheaper doing the small stuff for cheaper will leave you more room for bigger items dont forget a TUNE!!!!! unless you already have that and most places if you are a return customer will give you a cheap reflash.
otherwise... the above are some good bolt on mods, some of those htings you can get for cheaper like a catch can from corvettemods.com is much cheaper and a good design. Some tuning shops will do a TB port for $100, or you can do it yourself for cheaper doing the small stuff for cheaper will leave you more room for bigger items dont forget a TUNE!!!!! unless you already have that and most places if you are a return customer will give you a cheap reflash.
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Pro
Joined: Sep 2009
Posts: 671
Likes: 10
From: Tulsa OK
This is the best all around answer if included with a tune & cooling fan control; However there are various kinds of "go fast" goodies to be considered. How do you use the car? Autocross, drag, local cruises, road trips all would suggest a different focus. If it is used as a daily driver and a commute of any length is in the picture, I would stay away from new gears. With Corvettes, there are no easy questions or easy answers.
Good luck with you Corvette mods.
OBD
Racer
Joined: Feb 2011
Posts: 478
Likes: 0
From: San Antonio TX
Ive seen several used Supercharger and Turbo kits go for that, youll have to be patient to find one but theres nothing else that ill make you that fast for that amount of cash, just remember that you will need to plan on an extra 300 or so for tuning.
Melting Slicks
Joined: May 2008
Posts: 2,606
Likes: 355
From: Rochester New York
Racer
Joined: Feb 2011
Posts: 478
Likes: 0
From: San Antonio TX
Burning Brakes
Joined: Jul 2010
Posts: 835
Likes: 4
From: Los Angeles CA
http://forums.corvetteforum.com/c5-f...l-special.html
Team Owner
Joined: May 2006
Posts: 21,473
Likes: 356
From: Palmdale, Ca----- 2009 Cyber Gray 4LT A6 F55 452 RWHP 422 RWTQ- RIP 1998 C5 734 RWHP & 585 RWTQ-----
LS6 Heads (Used)
Comp Cam
LS6 Head Gaskets
Oil Pump
Lifters
LS6 Manifold (Used)
Do install yourself
Dyno Tune - to bring all the parts into tune and maximize HP gains!!!
Thanks,matt
Comp Cam
LS6 Head Gaskets
Oil Pump
Lifters
LS6 Manifold (Used)
Do install yourself
Dyno Tune - to bring all the parts into tune and maximize HP gains!!!
Thanks,matt
Drifting
Joined: Apr 2007
Posts: 1,760
Likes: 4
From: Broward County Florida
IMO I'd just save for a supercharger and then be done with it. I don't know what your goals are for this car but a lot of the all motor people regret having done so because in the end it's cheaper to just throw on a SC and along the way throw on a few more engine parts (ie LSX intake, cam, etc).
You also didn't mention if you're manual or auto, but with those miles you may want to conserve some of that $ for a new clutch or maintenance. Lots of odd things happening with my 2002 and I've only got 93k miles.
Small oil leak from rear main seal, mysterious coolant leak (not from hoses or cap leak), A/C malfunction, worn plastic headlight motor gear, etc.
I understand the desire for more go-fast parts, but be aware of planned obsolescence. Your car is 13 years old, something's bound to break soon.
You also didn't mention if you're manual or auto, but with those miles you may want to conserve some of that $ for a new clutch or maintenance. Lots of odd things happening with my 2002 and I've only got 93k miles.
Small oil leak from rear main seal, mysterious coolant leak (not from hoses or cap leak), A/C malfunction, worn plastic headlight motor gear, etc.
I understand the desire for more go-fast parts, but be aware of planned obsolescence. Your car is 13 years old, something's bound to break soon.