You can always go standalone. The HKS Vpro is supposed to work with the staged intake and 6 injectors of the renesis. There is a renesis specific harness available, which should greatly simplify wring it up. With a standalone, good exhaust, tune etc; a renesis should make comprable power to a bridgeport. Except, it'll have a smooth idle, quiet exhaust, better fuel economy and more torque down low... and oh yeah, the entire engine is only a couple years old. Plus, all the anciliary parts are new as well (alternator, injectors, coils, AC compressor, etc.) if you buy the engine as a complete pullout. If you were to build up a nice bridgeport motor, add a nice carb, headers etc, you're in almost the same amount. And, you'd still have 25+ year old sensors, distributor ignition, old induction technology, etc.

Think about it: a light FB, with a 9000rpm screamer. RX8 gets 24mpg epa highway and has a .850 6th gear, with a 4.44 final drive. If you use an FC transmission in your FB, you can get a .697 5th gear, and a 3.9 final drive, (or 4.0 with the -SE). With this tall gear ratio and a lighter car, the milage should go up by at lease 4 or 5. And because the car's weight is lower and with the added power created by the standalone and the exhaust, should be a good deal quicker than an -8, never mind a 130hp first gen.

Show me any other way to get a 275hp RX7 that is quiet and gets close to 30mpg...

Now a Turbo can make more power ultimately, but you loose the quiet and the MPG. And will more than likely, end up costing close to the same if not more to do it right. (Intercooler, exhaust, engine control)

RX8 pullout is ~2k
HKS Vpro with RX8 harness is ~1500. Bet if you can find one used, it'd be even cheaper.

If your FB already has a performance clutch and aftermarket FW, you're good there. Just need an a RX8 auto counterweight. Most of us probably have a spare front cover lying around. The rear is good for that power level. No need for a new driveshaft either. Oil cooler is no problem. If you have an -SE, fuel delivery should be as easy as upgrading the fuel pump. Slightly harder, but not that bad for a carbed car. No need for a header, which means you can just run a large single exhaust. No fancy, heavy and $ dual streetport exhaust necessary. Coil on plug ignition controlled by the ECU... so no ignition upgrade necessary....

That ain't bad. (Ask me if I've been pondering this for a while)