Is it possible to change the muffler tip on gran trismo 5?

i like to tune up the cars i have, so i go into the tune shop in gran trismo and i got exhaust, i almost always buy the racing system for exhaust, but when im driving i dont see any difference with the tip of the muffler, is there any way to change that, ( like if a car i buy has just a simple single pipe coming out the end, is there a way to change it to dual mufflers, or a bigger sized muffler tip then the one it started with)