its normally the key that fails if it locks off the key after a drive and doesnt work when you go back to it

always thaught it was BMW only at £200 a pop too

E46`s suffer with ABS modules failing giving random fault codes, multiple sensor failure, or brake pressure sensor faults as this is all internal, but remove, send off and refit repaired (dry joints normally)

worn bushes all over suspension

worn rear diffs if driven hard, clonking on drive takeup

clocks fail, loosing half of the facia, BMW only and 600+ (may be cheaper now, jump starting also spikes them!)

rear light clusters, take the plugs off the cluster, they currode like old sierras, BMW sells a repair kit, its a load of wires and terminals and chop out/repair and rebuild plugs

timing chains/tensioners fail over time

air leaks arround manifold area, need a good smoke tester to locate, regular emissions fail with high lambda circa 1.500+

harmonic dampers fail too, DO NOT unbolt the single bolt crank pulleys, this drops tension off the chain and cams jump!

wiring to outside temp sensor fails (located in either bumper brake duct)

heater resistor (hedgehog) fails causing flat battery
VERY VERY VERY hot, do not touch, leave battery off for minimum 2hrs
5 min job to replace though, dead easy

propshaft centre joints wear out, again clunk/knock on drive takeup

rear prop CV joints wear out and prop/joints twist and break the coupling seals, grease on diff joint is telltale sign

rear springs snap like twigs, again 5 min job on a ramp

rear brakes, as stated, handbrake is in rear disc, rarely used unless applied to a stop, 20 mins to change full braking system on rear

make sure a/c condensor has no currosion in lower half and corners

oil leaks from cam cover, sump gasket and headgasket!

thats all for now,

pm me if you ever need any help

Sean (master tech )