"UPP" gets used in two different ways, so you gotta check out the context.
UPP = 4-Star Ultimate Paint Protection. A sealant similar to BlackFire ("BF").
-OR-
UPP = 1Z Ultra Paint Polish. An aggressive, abrasive polish used to abrade away paint to fix sorta-serious marring. Must be followed by a milder product because it leaves micromarring.