I have tinted my side light lenses in my E36 with Lamin-x and mine have come out really well and were relatively easy to do. But personally I wouldn't suggest using and cheap eBay stuff, had a few friends do this and noticed that it starts to fade rather quick. So personally I would say either give them a good restore, get new ones or buy some proper lamin-x. But nothing to say they could do with a good restore to ensure the lamin-x is nice and bright and doesn't come peeling back off.