Intercooler question and piping
 

Okay, i currently have an RX-7 Intercooler. One outlet is on the back and is 2.0in the other is jutting out the side and is 1.35. Which should i use for inlet and outlet. Also, what size is the throttle body on a 1.8? is it the same as 1.6l (2.5in) Also is there a performance difference using one as the inlet and the other as outlet and vice versa?

Smaller for inlet, bigger for outlet

see 15 psi.com (no space) for an idea.