The old CAT and O2 sensor problem

Hey all, just a quick question/clarification here: ok so I put the flowmaster super 44s on my 91 coupe, and it doesn't sound much different. I wanted it loud! My technician says its because my car has 4 (!) cats. Now, if I take all four cats OFF and just run pipe where they were, will it trip my O2 sensor/check engine light? An off-road h-pipe is not in my budget. I'm told the O2 sensors are up below the headers (I have Mac shorty headers) and so I should be able to just pipe it through and remove the cats. Also, if i do end up tripping the check engine light, will it run badly or just be a light on that's annoying? Thanks for any help and EXPERIENCE.lol. (Ps I have no emissions testing where I live and I'm not worried how loud it is)

Yeah I am hoping it will make a big difference. A shop told me it would be about $200 to take the cats out and put a pipe in on each side. I am thinking about having this shop do it. But, I was wondering if those "flexible exhaust piping" things at autozone are any good? I could just cut the cats out myself and clamp the flex pipe in place. Good or bad idea?