These are quickly becoming valuable.
I'd say it'd depend on what you want to do.
If you want an investment, buy it. Keep it stock. They are appreciating like mad.
If you want to modify something, look elsewhere. These are like the Holy Grail to rotary guys.
I'm a HUGE rotary fan. For longevity I love the 12a found in the FA and FB cars.
I work on a 84 FB quite often for my friend. He's driven the car 100K + miles with very few hiccups.
Feasibly, they get poor gas mileage, consume oil by design, and the twin turbo system can be troublesome. Most swap to a larger single turbo instead, to simplify things.
You really have to WANT a rotary to own one. They certainly take a specific type of person.
My .02
I LOVE em.

EDIT: 'cept the RX-8, the Renesis platform can go fuck itself.
This post was edited by OldAndyAndTheSea on Jun 28 2015 08:26am