Rear end swap
 

Say if I suddenly get 265hp and 300lb. ft. of torque in my 4-lug open diff. RX7. What should I do? I obviously can't sit there spinning one wheel all the time, that'll cause the spider gears to seize to their shafts, and I'd eventually get little pieces stuck between my ring and pinion. So...

Is it impossible to change out the rear differential for a limited-slip type unit without changing out the entire rear end? In other words, what do I need to get my rear end to handle the power? Would this kind of power turn my stock halfshafts into quartershafts?

I'm not too hot on a 5-lug conversion because then I'd change so much stuff that it would end up costing me like $4000...

It all depends how much traction you are getting. If youre planning on running slicks, or even pretty wide tires, you will be exploding the rear end, or breaking 1/2 shafts left and right. You will want a Turbo2 rear end/axles. They are much stronger, have a LSD, and will handle that power no problem. Im pretty sure the axles will slide right into the existing 4-lug carrier assembly (someone please correct me if Im wrong) so you wont have to worry about the 5-lug swap. The only thing youd need to address is the driveshaft, because the T2 one is also much larger/stronger, and also is a slightly different length, and has a differnt bolt pattern for the pinion flange.

I'm in the same boat, well by the end of the summer I will be

Five lug conversion
 

The info about the difference in the drive shaft is accurate. I am doing a swap on an N/A. All you have to do is find rotors at a salvage yard and replace them it's fairly simple especially on the front, like six bolts. Get the four piston brake calipers if you can find a salvage that doesn't know what they have and you can get them for eight dollars a piece!!!! Stock pads are very good no need for aftermarket unless you plan on running a very good amount of power.