The worst one, in my experience of 20 years of running and maintaining my own nine two fours, is the bottom radiator hose, which at the engine end soaks up residual oil and swells up. Next is the crankcase breather hose from the flame trap on the block to the inlet air duct, but, the layout of pipes on the turbo charged cars is different. I wouldl still inspect it though. Less vulnerable but just as important if it goes as it did on my 924 t, is the 90deg bend into the thrermostat housing which at last count was unobtainable from OPC Reading, but the good new is that the bend on the bottom hose with the perished end can be cut off and used. It is a perfect fit, and the bottom hose was still readily available last time I needed one.
Finally lift off the aircleaner housing and inspect the steel transverse pipe that the thermostat hose fits onto. Tucked away under the aircleaner thay can get into a fearfull state. Now would be a good time to smother the M6 nuts inside the housing with plus gas, no, not wd (39+1=)as it isn't anything like as effective in my opinion, and I have done back to back tests on some rusty old tools that I unearthed in my wife's late father's shed.
