I'd never heard of them, but a quick google shows up their website and it looks pretty Kosher.
The problem is you really need to see the bike in the steel to make up your own mind about build quality, are you anywhere near their store? Unlesss it's an absolute steal that you could break for more than it costs you to buy I'd be very dubious about buying a bike off the Internet without at least seeing it first!
As to being 'trusted' if buying a modified bike from a dealer I'd be asking for some form of warranty, I mean you get the bike, they get your cash, but you want some form of after-sales service.