wow - it's been a very long time since i've posted. my twins are almost 9, and we have 2 more, ages 4.5 and 3. the 4.5 yo has outgrown his britax marathon based on his width. we're thinking of getting him a booster for this fall. where do i begin? are boosters at places like target worthy? or should i go to specialty stores? we need something that has good width since he's broad, and with winter coats, it's hard to get him buckled in.

thanks for any direction.
susan