depending on what you want, LS1 is a good swap no matter what anyone says. I personally wouldn't do it just because I'm a true rotor head. No matter how many problems I have with them, I'm all rotary. I've had a ton of them and always will. I've seen a ton of LS1 RX7's and they run great, if you just like the body style of the FD, then that is a great swap. I have seen LS1 FD's car in action and it's impressive. It will be when you throw that much horsepower and torque in a car that light. Like he said it does not throw the weight off that much, and there are ways to make it 50/50.

LS1 swap isn't cheap either. Nomatter what you do with an FD, be prepared to spend money, whether it's making the 13b reliable, or going 20b, or LS1. I'll do a 20b in the near future most likely just because I want reliable 600+ rotary horsepower, yes you can do it with a 13b, but it's way less stressfull on a 20b than a 13b, and I drive my FD as much as possible.