Rear tailgate glass seal
 

On my 2005 X5 I'm replacing the clear glass with the factory tinted glass. I already have the tinted glass for the tailgate and before I take out mine I was going to buy the new seal for it so everything's ready to go. The dealer tells me that seal only comes with the glass and it's $800 plus. So my question: is there a seal or sealant that I can use that will not leak and be the same thickness as the factory seal so that the glass well be flush with the body panels?