Clearance??
I'm going to try and drop the tank down, and roll up that flange. Thats worth a good 3/8th's inch there. Still have that darned strap, but I may reinforce it with a piece of 1/8" steel, then make a bend to buy more clearance. I just love the idea of using the stock tank. One unforseen issue was when I reversed the filler tube to re-connect with my new/old drag boat gas cap located on top of the rear quarter. The vent is now on the bottom, so on the first fill-up, gas dribbled out my vent tube under the car. I was wearing sandals!!! A new vent tube with a loop higher then the filler neck solved that problem.
A stock tank way up under the altered just looks right instead of a fuel cell:
http://public.fotki.com/teddisnoke/bmw-2002/22.html