Panamax 5500, where to buy

I'm looking to pick up a panamax AC regenerator, either the 5500 or 5510, and I'm confused about whether buying from an online dealer will void the warranty. The Panamax site seems to say just that but various sellers claim otherwise.

Does anyone have advice on where to buy a new unit at a discount from full retail/list price?

There is a list of authorized online dealers here.

The 5510 has been discontinued and the 5500 has been replaced with the 5500 EX. There may be a few 5510s still available. I have one myself.