I do love the RX7, but have never owned one.... For me, they are the Japanese equivalent to the European Alfa, quirky, things break, but in the end its worth it.
I have however owned a Supra. I bought it knowing it would require engine work (spun bearings), not a great deal of work. Standard engine is good for 600bhp and standard 6 speed manual gearbox is good for over 800bhp. I went the odd route of staying the twin turbos and ended up with just under 500bhp, with hindsight, a big single would have been move driveable. It was an angry car and I am pretty sure its only goal was to put me into a hedge.
Not the best pics, but you get the idea