I'm thinking of buying a used Class C and many of the ones I've seen have the Triton V10. I understand some early ones (before 2002) had a tendency to blow out their spark plugs, but this may have been partly due to over torque on installation. Does anyone know how likely this is to be a problem and what to look for on a used one? Also, what is typical for mileage and do the Airtabs make any difference in economy?