Add the cooling vent ducts from the 540 (IIRC) to the front, these brakes take a beating trying stop the big old girl and they appreciate the extra cooling performance greatly.

Poly bush all the usual parts then drop her down onto a set of progressively rated Eibachs with nice new dampers if yours are worn. The difference is night and day, including braking stability. 10 years and neigh on 2 tons takes its toll on all these parts.