I bought my S1 R33 (Nov '93) from Motorman 3 years ago (through Derek) - I know it wasn't the cheapest I could get one for, but it was my first Skyline and I was looking for someone to steer me in the right direction, and for $14,000 on road, complied, registered, I was happy - particularly with the service!
Derek went out of his way to find me a car with ALL of my requested specs, sent me options with auction sheets prior purchasing, and he even bought the car with no obligation from me to buy it! After compliance, he even sent me over to a Springwood exhaust shop and put an aftermarket exhaust on it for me - no charge. I've had NOTHING go wrong with my (older model) R33 to this date (touch wood!).
I am now in the market for an R34 GTT, and have had no hesitation in going back to Motorman - they will take back the R33 as a trade for a very reasonable price too.
I'd be interested in hearing what dodgy things they're doing Markimak - PM me please.
(it also seems strange that your gf's family would go back to them many times if all of their purchases were junk)