will a gutted cat cause me to be slower due to lack of back pressure???

[uno]

question plus i have a flowmaster exhaust....

[viper98885]

You will lose torque, but gain some horsepower. I have run my 3.4L with a gutted cat, straight pipe and a high flow cat and the combination that worked best for me is the high flow cat.

[Devious]

No. You need a little bit of backpressure but gutting the cat alone will not put you below that threshold. The concept of losing torque due to open exhaust only applies if you have a cutout or open headers.