Here's what I've learned in my time here. Or heard in person.
Borla = deep, mellow, quiet
Bassani = loud, high-pitched, performance-sound
Cardoc's = loud, deep, performance-sound
Brullen = loud, guttural, very dirty sound
SVT w/no res = loud, raspy at times
Magnaflow = deep, mellow, quiet
Dynomax Ultraflo = loud, performance-sound, not a V6 sound
SuperTrapp = adjustable, quiet, looks odd
So in my opinion.....Cardoc's exhaust is best. Hit him up with an email:
cardoc@fordcontour.org . Other than that, go for a custom setup like so:
-2.5" stainless pipe all around
-in place of center resonator, Dynomax Ultraflo
-Straight pipe splitting into duals all the way to the bumper
The above one is the ultimate sound I've ever heard from a Contour. My friend once heard it and commented, "That does not even sound like a car."