Re-molding plastic gas tank for rear stretch clearance

http://www.pirate4x4.com/forum/jeep-hardcore-tech/817258-rear-stretch-modified-stock-yj-plasic-fuel-tank.html

Has anyone done this in an XJ? I'd like to install a 14 bolt and stretch my rear ~3" back but don't want to lose the cargo space it would take to mount it in the back.
If so, what axle/tire size are you using and how much clearance did you gain? How much tank capacity did you lose?

Thanks

Hmmmm....isn't the fuel pump center and close to the front?