Help With Exhaust On Celica 190

[stgeorge77]

hello fellow celica owners i hope you can give me some advice....

i have a 2001 toyota celica 190. when i purchased it recently it had a modified exhaust. i asked for the modified exhaust to be replaced with a standard one as part of the sale. the new exhaust was still a little noisy but i took the word of the sales man that this was normal. since then i have been informed by a mechanic that part of the modified exhaust was still in place. i was not happy with this but felt i could put up with the noise as it wasn't too loud. the car was fine for a few weeks until i recently started it from cold and the exhaust was very very loud. it does get quieter as the engine warms up but have decided to take the car back to insist that the exhaust is replaced with the correct one. my question is (finally) how do i ensure that if the garage i bought the car from does in fact replace the exhaust like i asked them to, how can i be sure they use the correct one for my car? If they use an incorrect exhaust could it damage my engine and/or seriously affect the performance of the car? thanks and sorry for the overly long question!