the LR ones are crap! the britpart ones aren`t much better and the least crap of the lot are the allmakes ones, they come in packs of 10 and you will use at least 10 per spat. personally i use rivets
I find the easiest way to fit the plastic clips (genuine or aftermarket, they're all the same) is to trim the end of the pin slightly to give it a slight taper, slides in a breeze that way.