The 1JZ VVT-i actually had more improvements than just the variable valve timing. Besides the larger single turbo, it had a C/R of 9.0 to 1 where the standard 1JZ is 8.5, and the cooling channels were improved. Check out en.wikipedia.org/wiki/Toyota_JZ_engine for more info on all the JZ motors and their differences. The VVT-i has much more low-end torque, making it a smoother, more streetable engine, as well as more fuel-effecient (if that matters to you). Plus, from what I understand, I've heard you can squeeze a little more power out on the stock CT15B turbo than the 1JZ's twins. But like dennisupra stated, the oil pan is a front sump, so you would need to switch it to a rear sump to make it fit. The only big pain in the ass would probably be the wiring. Since the motor only came in the Soarer, you would need to splice the wiring harness in order to have your guages functional. Either way, both wiring harnesses are going to required extending as well, so the splicing issue is just an added step. The biggest downfall of the VVT-i is it's much more expensive, you can get a clean 1JZ twin-turbo engine and tranny combo for ~2-2.5k, where the VVT-i plus manual tranny is gonna run you ~3-3.5k. For cost purposes, your better off going to a 2JZ if your looking for big power.
