The porsche calipers were for Movit retrofit kit that no longer exists. You would need to fabricate custom brackets and a whole bunch of other things to fit it on a 540. My suggestion for a BBk is stoptech kit or even checkout the UUC kit (made by wilwood) for a cheaper alternative. If you have your heart stuck on brembo kits there they are available too but they are extremely expensive. There are 2 kits available from UUC. The cheapest one is just over $1000 USD and the move expensive is more comparable to the stoptech kit is around the $2000 mark( like the stop-techs). Goodluck and keep us informed about which route you choose.