I applied Showroom New to our Vx "Elvira" last weekend and was not at all happy with the results. I read everyone's posts on the procedure and was very careful to clean the cladding and strip any residue off. I applied a total of three coats and used liberal amounts, but in the end the streaking was unacceptable. I'm told that it's likely that the cladding had previously been treated and therefore wouldn't absorb the Showroom New. There is a little evidence of that since in some sections it scratches with my fingernail to gray, but in other sections it doesn't.
Bottom line: It's getting Line-x'ed Monday.
I've also read that since you can't tell if an old application of Showroom New or another coating has been previously applied, only trial and error will let you know if it's going to be successful. It was worth the $30 to find out, but I do wish I had known before I started.
My local Line-X Dealer quoted us $600 for all the cladding, hood insert and hood scoop in black with UV protection. He said it would take all day. So Monday, Elvira goes in to be Line-X'ed.