I did some further reseach and found that in 1998 the SL powerplants got the three-valve head upgrade as well as the twin-spark upgrade and posted an increase in efficiency and mileage. Any ideas as to robust-ness of earlier models (I'd have a hard time shelling $50k for really new SL when there are sooooo many cars available for that kind of coin - I'm looking in the mid-thirties). Thanks Elau and Ash for the comments. There's GOT to be a tech here (and additional SL owners) with an opinion too. If the powerplant on the 320 is the same as in the E-series sedans it shouldn't be any more expensive to fix, right?

Thanking those with the time to pipe up in advance,
Matt