You can press out the old bushings and reuse the housing. It is very difficult though and you'll need a press or special tool. You can get powerflex prepressed into the housings for $150. I bought mine from Bimmerworld too and I have no problems. (Powerflex).
You know it is possible to install the bushing too far onto the control arm. There is a certain distance you are supposed to slide them on (at least for the OEM rubber ones). I simply slid mine on so that only a small bit of the control arm stuck out the back.