the Apexi N1 holds up pretty well, and since you're car isnt turbo... it wont be an issue of blowing it out.

I would put the muffler out the pass side... it distributes weight a little better... like relocating the battery to the pass. rear of the car.

If i were you, i'd get a RB header, it'll make a bigger difference then any other pary of the exhaust. Also, the RB mufflers are very nice..and have a great sound.

BTW, any RX7 looks good with a large canister properly hanging out the rear bumper