I tried a search on the topic but am still uncertain. I currently have on my 93 SC3 the stock front cat, an aftermarket high-flow cat which replaced the mid, no resonators, and Magnaflow “Turbo” mufflers. My question is would removing the first cat completely cause the check engine light to come on? Also, the O2 sensor is before the cat so it would not be effected correct?

I believe there are a few members that have removed both cats on their SC3 but it’s been a while since I’ve heard anything about it.

 

I believe as long as you don't remove the O2 sensors, the light won't come on.

 

Just make a bung for the 02 sensors into the piping and you will be fine.