Was Apikol able to give you any support?
As far as I can remember, the Wagner kits seem to be the most complete aftermarket ones out there. The fact that they supply new ducting is a good indication that they thought beyond just making larger/better intercoolers.
I had mine made with bell cores and the stock end tanks and tabs have to be welded on the cores for the stock ducts to be mounted.
I've also worked with some SRM units that I thought were poor quality and didn't match some of the earlier ones advertised/pictured by them, where some fins were inconsistent or missing, the end tanks looked like they were cast in 2 pieces with a parting line and the mounting holes in them were tapped with M7 threads.
Good luck.