I've had $1,000 custom fabricated intercoolers break and leak... and also had $200 eBay intercoolers last forever. There is never any guarantee - regardless of what you pay for things, so I wouldn't let the $$$ spent be a factor.

Where are you going to mount the heat exchanger/radiator for the intercooler system? Air/Water IS super efficient - but you have to be able to shed the heat that's introduced into the system.