Well, since you are getting no replies, I'll chime in here.
First off, just for your info, engine/performance related posts belong in other forums. The blue oval lounge is geared more towards everyday discussions, not necessarily car related
You'll get more responses in those forums
As far as the exhaust, I am sure all the major companies will have set ups for the '05's (flowmaster, borla, etc.). I am not sure what you mean by it being a "viable " option or what kind of exhaust "solution" you are looking for. Get your '05 in your hands first and see how you like it. Then, if you want a meaner exhaust note, you can pick up an aftermarket set of mufflers. If you are looking for a complete system (headers, hi-flw or no cats, etc) then you'll need to ask in the Modular Madness forum. Those guys in there will know more of what the '05 will respond too.