First Rebuild questions
 

I recently got a 07 rx8 that is a roller. I started tearing down the engine and I found that one rotor was Rusty, and there was some rust where the coolest was on the rotor housing and on the irons. I also found a ridge on the rotor housing. There doesn't seem to be any flaking or have much chatter.
How flat dose the inside of the rotor housing have to be?
I was wondering how much rust is ok for the rotors, housing, and irons?
should I sand off the rust on the rotor, buy a new rotor, or leave it as is and hope for the best?
I have pictures of it attached

The rotor is whatever, you can clean it up. I would not reuse that housing if you want the rebuild to last any amount of time. It was likely overheated and there is really no tolerance for ridges.

Do it right or do it twice :)

Would reaufising be feasable, or will I have to go with completely new housings?

Do you want a 30,000 mile motor or a 200,000 mile motor?
There are good condition used housings, but new is always better.

I sense you're trying to cram "rebuild" and "budget" in the same process.

This is a bad plan.

You can do it right the first time or you can do it right the 2nd/3rd/4th time for 2/3/4x the cost of doing it right the first time.

INB4 the "I just rebuilt my engine and it won't start" thread.