Hey guys been doing things to my MGM little by little. Put a true dual system with FM 40s throttle body spacer and k&n air filter w factory air box. Today i had the lower two cats cut off but left the upper two so I can pass emissions. This is the 281 4.6 v8 with 4 cats all together. But I def feel a loss of power when I step on the gas it doesn't jump out like it did as soon as u hit the gas anymore but it does have more power when I step on it on the highway ??? Did I mess up doing this? Should I take off the throttle body spacer? People said it's a waste some say it helps. Should I buy new cats and put them back on? Any help would be appreciated. Also these are the original cats car only has 99,400 miles.