heres what i found for an intake for my 2.4lt/ 4 Cylinder. i think if it doesnt fit right im just going to have to add some piping.
K&N 576000 Nissan Cold Air Intake $139.23
Nissan 240SX 1991-1992 .K&N FUEL INJECTION PERFORMANCE KIT, 57 SERIES FIPK, GENERATION 2, COLD AIR INTAKE -- 50 State Legal, Replaces Entire Air Intake Tract And Filter, Reusable Filter Lasts Longer, Produces An Additional 8.66 Horsepower At 6300 RPM, Increases Fuel Mileage, Easy To Install, Larger Filter Area Increases Service Intervals, Million Mile Manufacturers Warranty, Replacement Filter Part Number RC-4690, GROUND SHIPPING ONLY.
Engine: 2.4L, 4 Cylinder, GAS, FI, VIN "M", KA24DE, MFI
Chassis: LE

Just be careful splashing thru puddles, your cai will inhale water, thats why i went back to stock, that is, if its an ope cone filter, if not, you should still be wary

welli just got new mud 31" mt tires and avoiding water/mud holes isnt exactly what i ahve in mind. so is there any way to cover the CAI or at least protect it better from water.

not reallly! Sorry dude! That is why I sold my CAI. That is why I also went back to stock. You can make the stock intake perform ALMOST as well as the CAI. I bought a K & N element and plugged some holes and then you are good!
Just did it like 2 days ago.

yea if you buy the one from Nismo it has a little separator thing.... and you would have to be in water up to the lights to submerge the filter... a little splashing would do anything, I've taken a hose to the filter at the car wash and the water goes right out the bottom.... i wish still knew were the article is but it shows how a bypass valve works on CAI's (the intakes available for the xterra are really not true CAI they are Short ram intakes) and they spray it with water and the engine is fine, remember a little water won't hurt your motor as long as its not hydro locked, ever heard of water injection? its were they mix some water in with the air/fuel via a injector and it cools down the intake temperatures. but in order for your intake to suck in a detrimental amount of water you would have to almost completely submerge the filter into water, causing the engines suction to pull the water up the tube

just search the type of motor and it should pull up all the diffrent cars that used it.....use yahoo or google