I actually ordered it from Adventon.com. They were pretty cool about it and were more frustrated than I was that Injen took forever to make some they could sell.
I actually just got in (test driving after the install) and it sounds pretty good. The install was kinda of a PITA. Mostly cause I think the 2003.5 model coolant tank may be different because I wasn't able to mount the coolant reservoir to the radiator. Lack of the tab pictured in the instructions. So I'll reinact my favorite McGyver episode this weekend and fabricate one.