Got cat put on for emmissions next month.They put on a Walker cat with clamps. All I have to do after I pass the test is undo clamps. Should I put a straight pipe in(2 and a half,I think), or put a cutout in the spot? Which one would give me the best gain. I have Lingenfelter cold air induction,1le elbow,airfoil, and Hooker muffler with ss tips.lmk thanks,Pickerman