If the engine won't turn over or cuts out at seemingly random times, it may be a failing relay for the DME system.
Porsche 911 Turbo Problem Reports
Most Reported Porsche 911 Turbo Problem Reports
Check Engine Light illumination and performance issues can be caused by oxygen sensor faults.
Engine oil leaks can occur at the rear main seal and/or intermediate support cover o-ring; a revised seal is available. A careful diagnosis with proper tools is necessary to verify dimensional accuracy of the crankshaft to engine block.