1st off - Congrats!!
like needsdecaf says, buy different bases for different cars. You don't want to wake them up to take them out of the car since sleep is important! 2nd is reverse facing car seats for infants might bump up against the back of the seat if you are tall. It's much easier if it's in the middle from my experience (at least that I can remember from the lack of sleep!)
The peg perego's are nice. You definitely want to buy one that's comfortable to carry but the base not too big.
2015 F83 M4
2014 X5 xDrive 50i M Sport