Sent my Jet Central Rhino in couple of months ago with 24.3 hours on it for its 25 hour service. Flat fee for 250 bucks to service and zero the motor.
With the older turbines you are flying you will have to bite the bullet for servicing. Some the newer motors come with lifetime service plans that cover overhauls for just a small flat fee. Jet Central is one and has had theirs in place for a while, and others are coming on board with the same service plans.

Take care.
Mike