Im still suggesting some good longtubes and ory, then e-cutout and stock catback. Loud as hell with the cutout open but still extremely quiet with it closed.
Although driving around with the cutout open, like i normally do, it causes a lot of vibration and is extremely loud. But hey, i like it loud.
Ive read on LS1tech that if you have a good catback you wont need a cutout. There's been people with only 1-2hp gains from the cutout once they have a nice aftermarket catback thats unrestricted. Although on the stock catback it does show significant gains.