haha !! i wouldnt put that turbo past 1.6 bar i dont think buddy, the i/c pipes should be same diamiter as turbo outlet on the hot side and then 2.5 inch on the cold side to the tb maybe 2.1/4 on a 4e ??????? but im not 100% - i wouldnt overly worry about the lag it just means that when your off boost your more economical - all you gotta do is shift down a gear
there are gain settings on most boost controllers aswell that can help with reducing the lag and also your tuner may be able to alter it slightly aswell but thats one for chris