Add a BOV (blow off valve) upstream of the intercooler if your running turbo with a standard trans. Keeps the turbo from trying to stall when letting off the gas to shift gears. At least it worked great for me on my old shelby z 2.2 turbo ll with 5 speed
Like moparmatt said, run a BOV between your intercooler and throttle blade so when the throttle slams shut on shifts under boost the BOV will relieve the pressure between the Turbo and throttle blades taking the pressurized load of the turbine bearings.
The boost drastically drops with each shift. The best application with a Turbo is with an automatic transmission. That way, you can keep the loud pedal mashed. Don’t get me wrong though, a manual trans and a turbo will always be fun! I had a Turbo T-bird (2.3L 5 speed manual) and a Grand National (3.8L Auto). Both were extremely fun, but the T-bird lost boost with each shift.