These seats were bought years ago but never mounted or used in a car. The frames/sliders are from B3 chassis but may fit the B4's. The drivers side frame has a cut off switch for engine but can be removed if you don't use it. I live in Los Angeles and these are a bitch to ship. The seats are brand new, just been sitting for a long time. This is a steal for these. Also have center arm rest that fits 5000's in same black fabric.