there used to be another brand of box, it used the stock 250r configuration in which the pipe came out of the box on an angle and gradually curved to the carb, eliminating the 45's of the CFM tube.
I'll see if I can find pics, I know there's some on here somewhere, I think lil speeddemon had one of these.
If I were to build a box, it would be that style
edit: here ya go, I found this thru google under SMS motorsports, which does not make blaster stuff anymore, I also think project Blaster used to sale a similar box, but they're gone too
it appears they're using the front half of the stock air tube on the one, others I've seen used a silicon reducer, and these are full width between the frame rails, wider than the CFM boxes to allow the filter to sit on that angle.
notice these are 2 different boxes, one tube enters the corner, the other the front face, but both were shown on the SMS website under the filters page.
http://www.snydermotorsports.net/productpages/airfilters.html
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