you don't have to do anything to the modulator, nor do you need to switch to a manual valvebody. You won't be in boost at normal acceleration, cruise speed, or just going down the highway, so the modulator won't know the difference. When quickly accelerating, you'll be in boost (at least somewhat) which the modulator will interpret as 0 vacuum, just like it would if you were naturally aspirated. The modulator only controls shift rpm when the tranny is in Drive. More throttle equals less vacuum (in your case this leads up to boost) which equals higher shift points (in rpm) when in Drive. The governor still controls max shift points. So, in other words, casual driving, shifter in D, tranny shifts like normal with the modulator hooked up in normal fashion. When driving a little harder, getting into boost, the modulator might raise the shift points a little, but modulators have enough adjustment to tune it out, if you like. When wide open throttle, just shift it manually like most people do anyway. Absolutely no need for a manual valvebody.
A C4 shifts more quickly, precisely, and consistently than any T5 could ever be driven. Never sell the C4 short, especially in racing. Overdrive is the only redeeming quality of the T5, been there done that, back to a C4 now and happier than ever.
so I ordered a B&M 2500 converter and a Turbo Action automatic and manual valve body and a Billet servo kit so I will see what breaks next
