An easier way to drop the charge temp is using water injection; Spearco used to offer a product in the $200 (US) range.
If you want to run an intercooler, I'd recommend a smaller air/liquid unit which minimizes pressure drop because you can put it right inline with your existing ductwork, and just run fluid lines to a small cooler up in the nose.
Also, Paxton used to offer an external cooler for their centrifugal superchargers, it was some sort of a pickup tube and return line that went through the dipstick tube on the blower, and the cooler was just an oil cooler plumbed to the nose of the car.
I'm surprised you're able to keep those two belts on, I had a Paxton on my RX-7 and if it was misaligned even the littlest bit I'd throw the serpentine belt in less than 500 miles.