This list of Last Step Products (LSP) I have tried and used is from Adams to Zaino and I probably have enough LSP products on my shelves to last 15 lifetimes.
I live is sunny south Florida and our harsh winters can be brutal (it got down to 29 once!). That being said I really can't really comment from personal experience on products to winterize paint.
What I have heard is that
Originally Posted by FX2ECO
"Collinite 845 or 476s both do a good job."
for winter protection. Both can be a little stubborn to remove (but worth the effort). They are not a wipe on wipe off like butter products but they both look good and offer real good winter protection.