last time im using gsr on my car,for me the best performance for it is vr4 intercooler if your engine is in stock form.
if u feel u wanna boots-up more than 1bar than the best is evo intercooler.
it is all up 2 u for your future plan on your engine. dont go beigger that this as it would increase lag and FC.
infinite intercooler also not bad, jus the weight is heavier than oem mitsubishi intercooler.
but my fav is evo intercooler! nice shape(garang!) and it is best for your future mod.
juz my 1pence.