Recommendations for chip if keeping cat

['86T]

Does anyone recommend a good running performance chip if keeping the catalytic converter? Unfortunately my cat is welded in and I live in wonderful emissions testing California. I guess if there is such a chip, I'd like it to have the same characteristics as a Thrasher 92 but run in closed loop at idle so I don't clog the cat. Is there such a closed loop chip? Running a test pipe is not an option

Thanks.