Have the coupe, but recommend the Peg Perego Primo Viaggio infant seat. More side head protection than other seats, infinitely adjustable knob for getting it set just right, and has a small footprint compared to other rear-facing infant seats.
Also, if you're still deciding between an infant seat and a convertible (front + rear-facing), my suggestion is to go with the infant. They're the most protective and allow you to keep your child rear-facing longer. But most importantly, they allow you to carry the baby in and out of the car without waking them.
'13 Individual Frozen Brilliant White ///M3 Coupe
Ordered 2/15/12 | Euro Delivery on 9/21/12 | U.S. Redelivery on 12/6/12 | Motor Dead on 7/15/13
'13 Space Gray/Mugello Red X5///M
Pavement Punisher | Snow Muncher | Family and Board Hauler | Roadtripper