I resent that. . . My 96 Ls automatic has an aftermarket exhaust and it sounds a lot better than many that I hear on a daily here in San Diego, most of them sound like beez when they go by rather than the deep sound they should have. . . You can buy the system from just about anywhere, but do you need the cat as well or just the exhaust. . . if you need the cat as well, then that is why the shop quoted you at $700, as they are pretty pricey.
not sure if Cincinnati is as strict as California, but a stock replacement cat is expensive. . . aftermarket ones are cheaper, but here it has to be C.A.R.B.(California Air Resources Board)legal. If it is not that strict there, then just ebay it. . . Got my exhaust there, looks good, sounds good, I've had it for pushing 3 years now and its all good. . . Didn't come with instructions, but all you need is a jack and stands, a ratchet set, a vice grip and about an hour. . .
Mine is just like this on my 96' Ls sedan:
http://cgi.ebay.com/ebaymotors/1994-...Q5fAccessories
if you need the cat as well then this may work depending on what you want to spend:
http://cgi.ebay.com/ebaymotors/ACURA...Q5fAccessories
if you are worried about it being cheap because it is on ebay, then you can get one of these:
http://cgi.ebay.com/ebaymotors/Magna...Q5fAccessories
Can even go skunk2 if you want,
http://cgi.ebay.com/ebaymotors/SKUNK...Q5fAccessories
but if your car is stock and no plans to upgrade anything, than any low cost one should work okay. . .
Mine is pushing 160k on my cat and it is still good(thought it was shot at one time, when I failed smog, but it was fine. . . you might wanna check out different shops to make sure you actually need a new cat. . .