Britax B-Smart 3 Travel System ?

Britax B-Smart 3 Travel System its a lovley buggy but need a smaller one as live on top floor flat and is so hard for me to carry up its in good condition normal wear had it 7 months carseat only been used about 10 times if that with the car seat u have the bit that goes inside for a new born baby its a head hugger but has a cushion that goes under there back so they have back support..with the buggy its forward facein or parent facein i have rain wear to with it and the carseat adaptors and cross bar and cross bar extenders...x