I have the Euro. 65mm SC pulley. Not many mods left that give a decent return for the price. If I added a 178mm crank pulley and pulley saver kit I might get the best return.
Another option would b to raise the shift points to 6500rpm. That would get the rollers spinning at a higher rpm and perhaps give good results keeping the revs up after shifts.
The pulley could be done with the stock injectors and the Kenne-bell boost-a-pump. It works on the Cobra motors running over 1 bar of boost. THX
I still would like to know what supporting mods you guys with the stack are running and the boost you attain.