Buy a voltage regulator, put it in, and keep the old one as a spare. Your idiot light will not come on when this part wears down to the limit.

Might want to replace your ignition tumbler now, rather than worry about it failing at an inconvienent time.

These two jobs are easy and cheap ($35 adn $120).

If you have a radiator with the plastic (non-reinforced neck), I would upgrade to the reinforced style. Not sure if this is the case with the 603 motor setup.

These three items are known showstoppers.

__________________
'90 300SE 298k
-300K and it gets put into retirement.
'80 300D 255k Purchased new by family in 1980.

Had a:
1973 220 (gas)
1980 300SD
1992 400E