I had a cat-bypass installed in my 91 S2 (the old cat was broken) recently. But the muffler is an old after market one which the previous owner installed. The tech at the shop also told me that even thought this after market muffler is too small for a 3 liter car and is similar to that of a Toyota Corolla in size, it shouldn't affect the performance, just the sound. Somehow this doesn't sound right to me. Is this true? What should be the correct size for a S2 muffler? It's extremely expensive to get a stock muffler here in Taiwan, and I am thinking of having the muffler and the rear end (rear tip?) custom made and would like to now how it should be. Many thanks!