incase anyone was wondering (diff compatibility)
 

despite a few rumors found elsewhere on this forum i have tested and confirmed,

the rx8 rear differential is NOT a direct swap for the FD. the PPF mounting points are completely wrong. I have been told that the ring and pinion are compatible but i can't verify this for sure. after calling around a few shops and getting ring and pinion swap quotes i decided that this mod is in no way worth the cost. something i dont understand... to put gears in my old mustang 8.8 averaged 200 bucks IN The car, how can it possibly cost 800 to install them in my rx diff OUT of the car?? they are extremely similar in design. insane i say.


anyway, just passing along info.

god i hope this guy offers refunds...

I think most here knew that the entire differential housing would not simply bolt up. The internals are the only things that are useful to RX-7 owners.

I would get a different opinion about getting the FD housing (pumpkin) set up with the RX-8 LSD, ring and pinion. It should be under $400 to have everything swapped in and set up properly.

thats what i thought too, i called three diffrent shops, one quoted 800+ the other was 580 and the other was 600. even if i could find one for 400 thats 400 for the install plus 400 for the diff itself, thats 800 for a questionable gain in performance, just not worth it. i'd rather put that into a nice intercooler or fuel upgrades. oh well.

You can get 4.44 ring and pinion sets from an RX8 for about $200.
This is just for the ring and pinion... no housing or pumkin which is NOT needed anyway..

GL

You could get the whole rear end on ebay for something like 250, learn to do the gear swap yourself with the right tools, and sell the unused parts. I've gotten a few rx8 rear ends on ebay and parted them out and learned to do gear and bearing swaps.