ca18det intake pipe size

[240sx_s13]

i am doin a ca18det swap in my 90 240sx. im not doin anything internally but i am adding a blow off valve and a 24x12x3 intercooler. im just wondering what size intake pipe i should use for maximum power and minimum pressure loss. im thinkin about using 2 1/2 inch pipe but im not sure if thats too big with an intercooler of that size on a stock turbo. any help would be appreciated. thanks

[WeldingHank]

i used 2 1/4 from turbo to intercooler, and 2 1/2 from intercooler to throttle body. i also have a 3" intake pipe going from my Z32 MAF to my S15 turbo.