I rebuilt my whole D-series with a new clutch, flywheel, bearings, rings, seals, gaskets, pistons and machine work for $650. If you can take the time to do all the work yourself, you'll save a ton of cash. The whole engine seal kit is under $100. Compare that to the cost of the timing belt parts, and the turbo kit, and you'll probably find it's more economical and practical to do it all at the same time. A lot less work that way. EDIT: ...and you'll know exactly what you've got to work with.

Cheers.