I am a verry happy owner of a 2.8 M104. The car is in good shape .Mine just turn171k last week . I got it in May 2004 with 145K but all those mentioned parts( head gasket, throtle actuator, wire harness, A/C conversion, new radiator etc) were previous changed.I assume, that in the car that you are looking at, the maintenance was done and there is a high chance that those parts are new.
Mine is very strong , i did 26k in 7months.trouble free miles. Now that I got hooked to mercedes I am looking to sell this one an to get a 400E or E420, so if you are interested I can send you some pictures. I am selling the car locally for $5700

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New Addition to the family
2013 Passat TDI 5Miles
2004 E500 4MATIC Wagon 95k
1996 E300 Diesel 173k Sold
1993 300E 2.8 230k Sold
1994 E320 White Wagon 373K Sold
Still dreaming about ....500E


Radu Negru