My Chicco Keyfit 30's fit my new X3 just fine. I have two of them since I have twins and I fit in the front seat without a problem. I am 6 feet 1 inch tall.
2013 X3 35i, Dealer Delivery July 2012
2014 550i M Sport, European Delivery May 2014
Gone, but not forgotten:
2006 530i, European Delivery June 2005
2008 335i Coupe 6MT, PCD November 2007
2011 550i M Sport, European Delivery May 2011