Thanks for the info. I'm curious what year, make and model you have. FYI-I've got manifolds now and don't plan on installing headers. Realize that sounds confusing (2'' outlet to 3'' exhaust), but if I keep this car, I'm putting in a big block (413, 426). A more high output/cube motor justifies going 3'' and as a bonus, I won't have to redo or respend. One and done, and the versatility should performance be tweaked in the future. BTW-This all started when a B body 3'' Flowmaster kit went up for sale and got my wheels turning. Called Flowmadter's tech department to see what mods would be needed to adapt to my car and the culprit ended up being the tail pipes. I'm not that handy and don't have a garage, so the exhaust shop will definitely be doing all the work. The question is: do I request 3'' or 2.5''. I'm thinking a good shop might just recommend going smaller from the start. It actually has 2'' or 1 7/8 on there now, so either will be an improvement.