I don't own an RX-7, I just recently bought an evo. This being said I'm pretty sure I want an rx-7 next; so I joined here to learn a lot more about them. It will be a few years probably before I can get one but I want to learn a bit more about them before I do. Two initial questions I have are - 13B vs 20B, are they two different engines or ? & Would I be better off buying a cheap rx-7 in need of some TLC or finding a mint one and paying more?

That's about it.