My friend has a 2000 S430 that just burned out the instrument cluster,dealer wants 1700$ for a part,anybody knows a source for a new/rebuild one for a decent price?

Good luck finding one. They are not just a "plug and play" unit. They have to be version coded (programmed to the vehicle).Plus the mileage is stored in the instrument cluster on that model making it even harder to find one(legally) . Good luck though, it will be interesting if anybody has any answers for you.