Skip Shift and CDV removal are two different things but both enhance the M6. At low speed the 1-4 shift is enabled and it's annoying. If your getting on it in the least bit, it's not noticeable. I put put around until my oil is up to temp, so for 20.00 it was a no-brainer for me. Actually got it from a guy for 10.. inc. shipping. The CDV removal provided consistency to the clutch engagement for lack of a better term. I believe it was OEM to help with driveline shock for folks who don't know how to drive a standard.
Congrats on the car, it looks great. Love the hood! Brass Monkeys would be nice for sure, I always liked them.