Chassis and Wheels

I just converted my wira to evo 4 engine, done 4wd, my spec are all standard with mines re-chipped ecu from japan(lucky i got it together in the halfcut)..

i just wonder

1.) my mech tell me to change the ori wastegate to tial, is it compulsory?? does the ori 1 din giv out constant boost??? or the boost not strong and cant out put the 2xx whp??

2.) with stock form, will it be easily tapau by the those street vtec (not heavy modded) , kcar turbo or some stock gsr?? (face problems...