you could always use turbo hoses that came on oem cars, problem is with that is its always pretty small from the factory. im going to use some starion, supra, and rx7 factor turbo couplers for the turbo side of my ic piping, im not going much larger than the 2" inlet, and they look to be tough as heck. probably 2-2.25 on that side--------im going CHEAP-er on this one by sizing the pipes along with my tb and turbo inlet needs.
routing intercooler piping sucks, no if, ands, or butts about it. one side of my turbo piping is gonna be sin ugly, but it is NOT coming off. the other side will look pretty good, probably a 2.5 to the tb. its true, a 200.00 ic will cost you 200.00 to plumb, if not more.