I just replaced my fws skytint with vkool 70 elite but I noticed there is not much difference in terms of the heat felt. I am just wondering if there is a way to tell if I am being cheated, ie. Whether the tint installer actually replaced with another cheapo brand and not vkool. The glass oso really hot when I touch it.. I wasn't given a certificate of authenticity either coz the guy say I only changed the front, will get a warranty card of I changed everything.