Welcome to NICO!This is a question that all depends on how much power you want, how much money you want to spend and how much time you want to spend on it. First off, its gonna be costly no matter which way you choose, swaps with nickle and dime you to death, period. Obviously the SR20 is the most common swap.. as far as mounts go and ease of placement, its the easiest. You also have the choices of ca18, rb20, rb25 and rb26.. theres a guy around here that has a LS-1 in his 240 lol. The sr20 and ca18 are the easy swaps since they both came in the car in japan. rb series is a little trickier but are more powerful motors. I dont know much on the rb20 swap but I know the rb25 swap is painful for you wallet, you have to get a new driveshaft and a bunch of other things. Or, the choice I didnt mention, the choice Im taking (because I like being different) is the turbo-ka. Pretty cheap to scavenge parts, depending on the setup you can get into stock SR power ranges (~210) for about $1000.00. I only reccomend the ka-t option if you know what you are doing and/or have friends that can help you constantly. As far as power, here are the stock charts:ca18det: ~175-s13 sr20det: ~210s14 sr20det: ~240s15 sr20det: ~300-rb20det: ~214rb25det: ~247rb26dett: ~280 (dont know of any 240's that can use both turbos on the 240 swap)
HP figures taken from the follwing websites, also some helpful links.
http://www.nissanca18det.com/http://www ... royon.com/
Goodluck!