At the end of the day, Niz has paid his membership fee the same as everyone else and is entitled to seel whatever parts he has to offer.
If the prices are too high then simply don't buy them.
As for the parts being tat, yet again, don't buy them if you think they are tat.
Niz's sales feedback indicates that not everything he sells is tat.
I agree, that Niz does appear to have everything from the kitchen sink to car parts for sale but it doesnt mean you have to but them.
If the mod's feel that he is attempting to scam people out of their money or is mis-selling an item then they will deal with it accordingly.
At the end of they day, if you dont like the look of what is for sale, just dont buy it. It isn't rocket science.