I agree. Valved, valve lifter and spring replacement is not very characteristic of this engine.

M103's are notorious for valve guide wear, though.

That might be all you need to do.

__________________
Paul S.

2001 E430, Bourdeaux Red, Oyster interior.
79,200 miles.

1973 280SE 4.5, 170,000 miles. 568 Signal Red, Black MB Tex. "The Red Baron".