I have a 96 9C1 Caprice with stock exhaust tubing. I ordered Summit turbo mufflers to replace the stock units, size 2.50. i cut the old muffs out as close as possible, and I belive the stock tubing is 2.25, how am i supposed to fit the new mufflers to the old tubing? It is much largerin diameter, is a reducer/expander needed?