the cfm box actually sits farther back than a stock box, allowing ample front to back room for the rezzie, it's the right to left angle of the intake tube thats damn close to the 400ex rezzie, but i'm fairly sure that combo has been used by someone on here.
I will say this, If the factory 7 boxes weren't $200 they have better flow as the tube from the box to the carb is3"reduced to 2" mandrel bent.
Pic below! Diserio Image - Store Machine - Project Blaster
The CFM ones are 2" 45 sharp angle and may require some mounting mod!
The holes in my box did not line up with the mounts on the frame were you bolt it on so i just welded a new bracket on and one to hold the rear too i want no movement at all!