Ok just got a set of rims 9.5 wide all around and et30 all around but I was thinking the rear needs a little more width so what would be a good spacer size to add on.

 

There are 3 generations of RX-7. Which one is yours?

 

Fd3s

 

9.5" wide with 30 offset should be pretty close to the edge, unless you are running under minimum sized tires or you got aftermarket flares/fenders
either way, provide more information if you want more feed back

 

Ok well no arch work I have coilovers which il adjust to suit and there is no tyres yet as I'm waiting until I figure out the spacer situation so I can get the best tyre size.

 

A rolled rear lip will make a good 10mm different in how far out you can go. It you are trying to go really flush with normal camber and roller lip you could go with a 10 or 15mm spacer. Not rolled I'd leave it as is or just a 5mm shim. Your tire will also matter a bit as section widths can vary by over an inch for a given size.

9.5 +30 is going to be a bit wide out front unless stretched or rolled/pulled or high camber.