I got the axle back Flowmaster Force II kit.
It was cheap through Amazon at the time, $260 free shipping too.
It sounds good on the 3.6l, low and deep, startup is really nice, however, it is a bit quite for my tastes.
I had an issue with fitment on the first one I ordered and they sent me a new one without taking the old one back, sold the new one to a person with a 3.8l for what I paid and it sounded a bit farty to me, but he liked it. A little louder than on the 3.6l, I think it has something to do with the resonator on the 3.6l. I am going to modify the first one I got with a smaller can to make it louder and fix the fit issue. Note that the pipes are stainless but the delta 50 can is not, it has started to rust a bit through the black spraypaint...