I don't know if I can help you but I'd say that there is one thing I noticed with these Camries. If there is only one thing that lasts for years and years on these cars, then that would be the exhaust pipe. Mine is more than 200,000 miles and 12 years old, never changed anything yet. It's even not that I am lucky as I don't seem to be the only one. I have never heard of any other brands having such long lasting exhausts. So I would say if you only want to keep the car for a few years then go for an aftermarket one, if you plan to keep it for as long as possible just buy a new oem one (or even a used oem). You can try to find one on ebay, there sometimes are a few for a good price.
In fact as 5spd V6 ClrTail is saying it might be just the flex pipe (it is actually the only thing I changed on mine). You can't find it as an oem part (you'll have to buy the whole first part of the exhaust) but it is possible to buy just the flex to some companies (I found one on ebay for 10 $). I hope I wasn't to long

Good luck anyway !