Re: Car Seat Dilemmas...help!
Recaros are not short shelled but they do narrow at the top and don't provide a ton of shoulder room for taller kids. They do not provide much rear facing leg room.
For the 4 year old, I would get a Maestro or a Harmony Defender.
Look at the Guide 65, Evenflo SureRide, Graco Size4Me (the MySize and Headwise are other versions of this seat) or a Radian since he's a big guy.
CPST-I and SAHM to DS