How big of Intercooler piping?

[Forced Fed]

Stock it comes with an intercooler, shouldn't I atleast retain the original intercooler?

Or swap it for something better like a 1g SMIC I have laying in my living room for basically free, just reweld the endtanks?

Edit - There is room under the hood for it to sit like a normal FMIC, it wouldn't be a top mount or anything.