Here are some useful sites for current and would-be owners:
http://robrobinette.com/
- Helpful guide on buying a used FD and good info on reliabilty mods, pros and cons...
http://www.rx7club.com/
- A forum with loads of helpful info
http://www.scuderiaciriani.com/rx7/
- FAQs, how-tos, general infos...
Contrary to popular belief, it is not impossible to have a healthy and reliable rotary powered car, be it modded or not.
Give it a good read through and follow the recommendations. With the knowledge gained through these sites, you can actually be your own mechanic.