Yes I hear what you're saying Rob. But I think the point Alan was making if you buy your parts from Vauxhall/Ford/VW or wherever it will take away the hassle factor should there be a problem. I'm sure aftermarket parts which are OE compatible are fine it's purely the fact that if you buy your service parts from the dealer it's one less thing to worry about should the warranty come into question. Once they're out of warranty carry on as normal fitting Mann Hummel/Bosch/NGK/ or the like.