I was wondering if anyone knows if there is a way to remove my cat and put a midpipe with my stock exhaust

 

Yep, remove the CAT and in it's place install the midpipe. Nothing special to using a midpipe with the OEM cat. The only thing I think is with the TurboXS midpipe, I don't think it works with stock type exhausts. The below thread might be of help, the fact that I have a Greddy SP2 doesn't change a thing for your future install.

https://www.rx8club.com/series-i-do-yourself-forum-73/diy-racing-beat-resonated-midpipe-install-194450/