More of a warning against that guy's business practices.
A warranty should be honored. In this case, I was accused of cleaning them in acid. The owner of Hilkoil obviously doesn't have a clue about the market he's in ... or he's just being deceptive to make a buck. After dealing with them, my money is on the latter.
I'd recommend these guys over Hilkoil any day: http://www.therma-coil.com/
They can custom build any coil you want, too.