I noticed youve listed an RB25 as a possible swap, I would not recommend you go through with it if you dont have a fair amount of money sitting around or dont mind working on the car and saving money for a year or two. Im doing an RB25 swap right now and Ive spent over $7000 (including cost of car and back registration fees, $700) on it so far. Its not even running and I still need to buy parts to make it run. My brakes, suspension and all that is stock. My car looks like complete crap as well. To get an RB25 with suspension upgrades, brakes and all that and having the car look decent will cost well over $10,000. Dont let the price of the engine fool you, it adds up very very quick just to get it running. Unless my friend, you have driveshaft fabrication capabilities, can make a custom wiring harness, can make engine and transmission mounts, make a custom exhaust and obtain an engine that is complete and hasnt been in a front end crash (difficult to find), which cut the cost dramatically.