any body running a fuel cell UNDER your trunk floor?

I have a 16 gallon pro street fuel cell,i am planning to do away with the spare tire well,and mount the cell under the floor.I would rather use the 45 degree fuel filler neck,and connect it to the factory fuel filler neck,if thats possible.i know it will be a little more to the center and towards the rear slightly,but i noticed the factory fuel tank is set more to the driver side.Since i plan to run a side exit exhaust,why cant i leave a 1/4 inch gap between the fuel cell and frame rail.This way,the filler neck in the fuel cell will be more to the passenger side.This would also free up enough room for the electric fuel pump,and canister filter.Another question is,should i run a return line back to the fuel cell,what size should it be?Im running 6 an braided hose.

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