the 535 had the option of a m sport package which included a body kit and the m style 18" wheels - i believe this only became available in 2009 since im looking to a buy a 2008 with the m sport package but have yet to find one
the kit is available after market, note the rear bumper has 2 exhaust openings
http://forums.5series.net/index.php?showtopic=77090