The 603 IMO has problems if overheated, with the head cracking. The manual shows an improved head gasket to fix early gasket problems with oil leaks and coolant leaks, same with the 602.

If you don't overheat the 603, it'll treat you fine. Plenty of them around with 300,000+ miles and original head.

The 602 engine is great also, the only significant difference being the later car's electronic boost (wastegate) control, which opens in the absence of vacuum, some have backdated to the earlier system which defaults to closed wastegate. Look for a lack of boost on '90s 300D cars.

I'd take either one. The later car has nicer interior panels and some nicer features along with the plastic lower-body panels to update it, the earlier more power. So far I've stuck with the '87 for the power, but if the right one comes along I do miss the interior of my '91, I'll buy another.

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Gone to the dark side

- Jeff