The failures you mention were on the thrust arm bushes BEHIND the track control arm overheating from the exhaust downpipe. The washers were fine but this only occurred on a small number of cars and only ever on the exhaust downpipe side. Powerflex were naturally unable to check if the affected cars still had the heat shields in place.

The X5 thrust arms are forward of the track control arms, away from the heat and are a completely different design to the saloon bushes. There are no washers either side and the bush is conical either side of the arm, not flat and sandwiched between washers. I know for a fact, that the X5 bushes are not, and never were available in the race spec, special order, harder black material.

I can only say that my Powerflex bushes have transformed the feel and handling of my car and are performing without any issues at all, both thrust arms and subframe.

__________________
Black E53 V8 on 20's, lowered, drilled discs and poly bushes, strut brace and adjustable sway bars.