as for uncommon I had a Remus exhaust with a Remus muffler. It sounded really good and looked almost stock. I dunno if there is a retailer in the US for Remus, the one I had on my 95 had it on there when I got it.
These are some sample sound clips on Euro cars. They are full remus but you can tell they don't make the cars sound real ricey or like wanna-be v8's.
Here is the site. They are out of Austria so I am partial to them but I really loved the sound on my 95 SE. One muffler with headers, no rasp and never got pulled over for loudness even though it was loud as hell.
Edit: Just looked at the site, they have a sample clip of a Mondeo with and without a Remus exhaust, sounds pretty nice IMHO.