you're paying for:
2. R & D
3. yes, maybe a bit of a BMW premium.
for each and every intercooler that's been sold here, i've seen evidences of constant testing to back up the product's effectiveness. the research and results put forth by the vendors/manufacturers give the consumer reassurance that the product WILL do its job. i'd like to see that kind of credibility on eBay/no name sites.
that's what you're paying for. not for the hunk of metal with two tubes sticking out at each end.
speaking of which i need one...