You're stupid~!!
Just kidding.
1.) an FD is the chassis code for the 3rd generation RX-7; FD3S. They are not that common like most cars. They are getting hard to find. They were in production in the U.S. from 93'-95'.
2.) For a rolling frame with no motor/burned motor/blown motor, expect to pay a lot if the body and everything else are in good condition. I've seen them go as much as 14k with aftermarket wheels and no motor, but with a perfect body. Check ebay, i've seen many selling there that need to be "restored" Usually they go for no less than 5-7k, again depending on the body.
3.)They are all pretty much the same. 93's of coarse being the first year have small problems such as a very harsh bumpy ride, due to (in my opinon) the best stock race suspension made on a sports car. The 93's also had a lot of recalls on door panels and minor misc things such as this. 94' up are typically the best canidates for a good smoother ride and cleaner non rattling interior. But, you'll never find a cheap 94 or 95 model even with no motor.
4.) I've seen the stock rearend take as much as 550rwhp. But it really depends on who you ask. Most people will tell you no more than 400rwhp on the stock rearend. I personally know a few people that have torn their rear end apart on the highway with around 350-400rwhp.
5.) Not really sure what you mean, but here's my best guess. You will not drive a more race like car in your life. The steering is very good on these cars. I'd say it's different than most rwd cars just because of how well it handles in steering. With not much body roll and nible handling, it really is a blast.
6.)Not sure on this one.
The more and more i read your post though, i am thinking; Have you ever driven a good running FD3S rx7? You'll be pleasently suprized on the over all drive of the car, light-wieght and powerful, you'll think you're driving an indy car. You're prediction of 420hp and 400tq sounds nice and all, but just wait until you've driven an RX-7 with that much hp.
Not trying to talk you out of it, but I personally think it's a waste to do this on a car that is meant to have the Rotary engine. The car was built around it and is the heart and soul of the car. Just my opinion. Either way, good luch with your project, hope it works out for you and I hope I helped you out as much as I could with your questions. If you're curious and want to read A LOT. Go to
www.rx7club.com and search for the member; Jimlab He is also doing a V8 swap in an FD3S, I think he has some of the most useful information on anything V8 and that of automotive info in general. Have fun!
-Marshall