i've got a 130PD and over the last 3 years or so I have replaced..
clutch & flywheel replaced (remap killed it lol)
wishbone bushes
rear beam bushes (need doing again - 60K seems about their limit)
cambelt & water pump
window regulator clips (fail for a pass time until replaced with the metal version)
rest have been upgrades / modifications / fancy shiney things
Thing to look for with the 150 is that the correct oil has been used - you may also want to check for white smoke / lumpy idle as well as the performance as the camshaft & rollers can be prone to failure on them even though it uses the same camshaft as the 130

only other way to double check is to whip the rocker cover off but that's a little extreme when viewing a car