First off... F*CK the losers that you go to school with.
Second... putting a new CAI in is very easy. Its pretty much unbolt the old one and bolt in the second.
Third... I have no idea. I dont know much about early 90's Rangers.
2002 - XLT, 4.0L, 4x4
3" BL, 295 Nitto Terra Grapplers
K&N FIPK, Dual exhaust