[twinmill28]

I made the mistake of dropping $800 on a Magnaflow system for my brand new 300C back in late '05, man I was so disappointed it wasn't funny.
Yeah, it made a slightly, and I mean slightly louder rumble than stock, but went right back to stock sound when I revved it up or ran it down the street.
Yeah, $800 bucks down the drain. And I only installed it for sound, I know better than to expect any noticeable difference with exhaust only.
I have done the glass pack route, installed one on my H3 after dumping the muffler and resonator--boy it sounded kinda cool, but droned driving thru the mountains and also pulling a trailer.
I've been seriously contemplating the OP's exact exhaust set-up, thanks for saving me over a grand for disappointment.