I've ordered from them a few times and so far so good. I also just ordered a set of old school GT525's from them and they even had a set in stock. (I know gt525s are old but I'm on a low budget for the Z right now and need turbos).
I'm not defending Z1 but just saying that we can't get parts from just anyone anymore, including the dealer. I'm glad that SZ, Z1 and CZ (and a few other smaller vendors) are still supporting our old cars. I do my best to support these vendors and hope they continue to grow.
Ken 91TT
P.s. I hope Z1 does the right thing and the forums are a good way to keep vendors honest.