Wait a minute so money is not unlimited for this?!?! What about wait time? If you can wait 3-4 months for it to be built I would look at Fast Intentions. Go non-res and it will be very loud. I just put my 18" res with HFCs on and it is loud when on the gas and sounds great at idle. I can't imagine how loud the non-res version would be in comparison in person. It will run you roughly $1400 or less depending on if you go resonated or not. Unless you want CF cans that will cost you $275 more on top.
There are some vids in the link.
Fast Intentions