Me too. I have the same problem from time, to time.

The gear indicator on the HUD shows your the gear you are going into before you let out the clutch.

 

It does take a little time to learn but here are a few things I found:
Learn to trust the reverse shift lockout. When going from 7th to 6th it’s then like going to reverse! Actually I seldom do that. You’ll find since you have 3 overdrives, rowing thru the gears like a 4 speed is not rational! I only use 7th when going 75 on the highway. In fact I’ll use 4th on the onramp then switch to 7th when up to speed. When leaving the highway I switch to a lower gear like 4th for the off ramp.
Use rev match in you’ll love the casual 7th to 4th shift matching perfectly.
Shouldn’t be difficult going from 3rd to 4th that is where the spring centers the shifter. Just pull straight down. Both fight the spring.
Rev match does not work going into 1st so any over-revving is due to trying to shift when you’d be near redline!
When using rev match and skipping gears, when downshifting DO NOT put the shift lever into another gate first. It warns not to do that, which for some folks was a common practice. I’m guessing the Hall Poistion Sensor that is predicting what gear you’re going into gets the computer confused! Therefor if going from 6th to 4th, or even 3rd, (something I commonly due when turning onto another rural road,) don’t put the shifter into 5th and then 4th with the clutch depressed. In my C6 I would often do that when I went from cursing at 60 mph and turning onto a side road. I would put the shifter into 5th, then 4th with the clutch depressed then heal-toe into 3rd so I could accelerate on the new road. With the C7 I just go from 6th directly to 3rd (that’s only 3700 rpm) let rev match do its thing and accelerate back to 60 mph (or faster!) Only cows on that 1 mile long wide open stretch near my home!
Get a CAGS eliminator.
I didn’t install an aftermarket shifter but did a large Cue Ball Size shift ****. I find it does make the side to side movement easier. I don't find the shifter "mushy." I've had my car since October 2013 and love the M7. I use rev match all the time

 

Thanks for all of the great advice. For the record, I meant to say 4th to 5th gear shifts I often end up in 6th.

CB

 

I find when shifting up by using the palm of my hand instead of gripping the shifter in my hand works well. So from 2nd to 3rd just push it upwards with the palm of your hand.

 

Once in a while when downshifting from 5th to 4th, It will end up in 6th or going from 5th to 6th, ends up in 4th. The gear indicator has helped every time! I won't let go the clutch until I see that it is in the correct gear! A quick flick over and I'm good!

 

Hand placement and practice.

 

You must have gotten your numbers mixed-up again. Grabbing 6th from 4th when 5th was intended should be an impossibility. Not giving you a hard time, just trying to clarify. Cheers!

 

No kidding.

 

A Shelby Cobra replica!? The only car I've wanted as much as a Vette. You dirty dog.