If the alternative is $1400 for seals by someone who is blind or $2500 for the whole deal there is no choice. Since the proper alternative should be seals for $450 versus $2800 for the complet job when necessary. Whats the decision.
Obviously if your tech can't tell when to do which, then its Russian roulette.
We are doing a chain failure on a grey market 420SE this week who knows how many miles. Four exhaust valves bent like pretzels. Virtually no wear in the guides we are replacing. I would never do a valve job without the guides, but untill there is a real reason, I let my customers keep their money. Anyone wishing to do the whole thing anyway, no problem.
Bosch Master, ASE Master, L1
33 years MB technician