Do you find the Xpel dulls the depth of the world pearl white? I'm also concerned of the Xpel yellowing over time. I have a full Xpel wrap on the front of my old white Benz and it yellowed noticeably over the last 3-4 years. On our black Lexus, the front wrap is completely invisible. To be fair, I really don't take care of the Xpel. Just regular drive thru touchless car washes every once in a while.
I believe XPel Ultimate is guaranteed for 8 (or is it 10) years. If it yellows before then they will replace it.