Whats the best intake to put on an A4?

 

Apple, meet Orange.

You're going to get many different opinions. Blackwing and Vararam are going to be at the top of the list.

 

I like the vararam, but it is the only one I have tried. From reading threads on here for a while here is how I would approach it. If I did not want a vararam or a CAI that modify's the radiator shroud, then I would not spend money on an intake that just replaces the stock air box. I would do the zip tie mod, and open up the fog light shrouds.

 

It's a good thing I saved this info!

If you live in California, think twice about the Vararam, as it can be a royal pain to install/uninstall/reinstall for smog tests. If you live in a state that doesn't have visual inspections, then take a look at the following (grouped by cold air and non-cold air, but in no particular order) and my comments, if any:

Vararam: Brings cold air in through the fog light panel area to a panel-type filter. Owners have had good luck with system on the dragstrip, but plan on spending hours to install and a bit more to get everything lined up well. Downside: Eliminates engine bay-cooling air that would've come in from the fog light panels (Z06 or coupe/vert with opened-up panels), so the engine bay may end up being toastier, especially if you add headers later. $350-$400

Vortech Rammer: Brings cold air up from in front of the radiator and into an enclosed box. Its filter is quite a bit smaller than the Halltech Warhead or Blackwing unit. $250

Callaway Honker intake system: This one relocates the MAF so that it is just in front of the throttlebody. It directs cold air from underneath and costs about $500. I believe this unit is 50 states legal (smogwise).

K&N FIPK: This is more of a semi-cold air system, as the cold air intake opening is more of a slit. Its filter endcaps are carbon fiber. However, it is configured similarly to the Halltech Stinger-R and is 50-states legal. $350

Warm air systems: (Easy installation)

Halltech Stinger-R: Not only contains the massive Warhead filter, but also includes a larger-than-stock airbridge and smooth throttlebody coupler. For $239.00 or less, this system represents one of the best bangs for the buck. Fortunately, for about $40, you can add cold air induction. See my procedure at http://www.conceptualpolymer.com/corvette_c5_corner.htm

Halltech Stinger SSM – 2001-2004 C5 only (new!): This intake system features an even larger filter than that of the Stinger-R, TRAP, and Blackwing. $400

Blackwing: Includes just a large filter, but an excellent one at that. Its cost is close to that of the Stinger.

Volant Twin Cone: This system gives you more open filter surface area than any stock box does and is well suited to an engine bay that gets cold air in from the fog light panels, as the filters are more or less in the air flow path. $265

2002+ Z06 airbox cover: A larger opening allows more air to be drawn in through the filter. Expect up to a 5 RWHP gain from this simple swap. $50

Zip-tie: An easy and inexpensive mod (eliminates the OEM box’s upper lid), but its sealing ability is questionable at best.

How good are they? My experience has shown that most will bump up RWHP by at least 10. The advantage of having cold air is that power will not be "dialed down" under normally hot underhood (and intake air) conditions. You could easily lose 10 HP with a warm air system after engine bay temps rise during slow-moving conditions. Cold air prevents this from happening.