I have the chambered exhaust system on my car and absolutely love it. (Santa was good to me last Christmas). The system on my car is the one that is featured in both the Eckler's catalog and the Mid-America catalog.
I did not want to cut into my factory exhaust, so adding the muffler eliminators or cutting off the resonator was not an option for me.
If you read the description in the catalogs, it advertises that the chambered exhaust sounds very much like a mid-year with side pipes, and I would have to agree with that. In my opinion, the factory system makes these cars sound like a Buick, the chambered system makes them sound as they should have out of the factory.
It is an aggressive sounding system. The idle has a nice throaty rumble to it and the revs are aggressive as well. Installing the system only left me with one question, "Why didn't I install it sooner?"
I agree with you in regard to the side pipes on a C4...just does not look right. If you are looking for an aggressive sounding system, this may be for you. It has more bite than the Corsa set-ups that I have listened to.
If you could listen to it in person, that would be ideal.