I've used Ultima before and I agree, it's good stuff. However, when it comes time to prep my car for the winter, I put on 3-4 coats of Klasse SG. The reason I use this is because one spring when I washed the car with Dawn prior to claying, I could actually see the SG dripping off the car. If that could hold up to snow, salt and car wash detergents for 5 months, it's a winner.
BTW, looks like we have twin cars. Red/black, M sport, 18" wheels. Nice!
2006 525 xi, Orient Blue Metallic, Beige leather, Dark Poplar trim, Premium Package, Cold Weather Package
2012 Z4 35i, ED 2/24/12, Melbourne Red Metallic, Black leather, 6 MT, ///
M Sport, Premium Package, Premium Sound Package, Cold Weather Package, Nav, Comfort Access, LED Angel Eyes, BMWPedals pedal covers, stubby antenna, Luxon strut bar, CF engine cover, LCI side marker, powder coated calipers, Extra Enjoyment Package