I dont know Trond personally, just thru different forums. I been looking at the backbox option. I have the Blueflame exhaust someone know if this is louder than others?Don't discount the value of custom exhaust places though; I would suggest that you'll loose some of that power going to a 2.5" system, but it will be quieter.
I'd keep the 3" system, but as you say, get some resonators welded in, and maybe a back box too. - PipeWerx have built some good systems like that, but the postage would be a killer.
Is Tronde the man in the know?