The aluminium front subframe fitted to the E6*  M5/M6 is prone to failure at the point where the roll bar  bracket clamps to the subframe. Once this point starts to weaken and bend, it can lead to the subframe tab fracturing or the bush clamp cracking.  PFF5-4203PLT is a high-grade zinc-coated steel plate to strengthen the subframe at this point. FEA testing has shown the addition of  PFF5-4203PLT,  to reduce stress in the subframe by 22.5%.