PM me and I will send you a jpg, hand drawn of course for now, but you'll get the general idea. I use 2.5lb soundproof foam for my noise suppression systems. Makes the box a bit bigger but if you have a dual fan arrangement on a single rad like I do, you are working with 18" wide by 12" high and about 20" deep. The ducting is set up almost like a subwoofer using a right angle baffle as the air intake. This way you can pad the air intake and exhaust with sound insulation and mount the pump inside on either springs or rubber bushings. Rad and fan also mount inside about 6" from the right angle exhaust duct. I keep reservoir outside.

Cheers