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, Alpine HID Angel Eyes, BMWPedals pedal covers, stubby antenna, Extra Enjoyment Package