Porsche 993 Turbo smoking upon start-up?

TurboKraft's oil line update package is the solution to this common problem! 
The most common reason a 993 Turbo smokes on startup is the turbochargers siphoning oil from the engine after shutoff. This over-fills the drain reservoirs beneath the turbochargers, until oil pushes past the turbochargers' seals.  

Less common is the problem of oil draining back into the turbochargers from the crankcase.  If your car has this problem, we have a solution.

Very rarely is the smoking at start-up due to worn out turbochargers, or worn valve guides and/or stems seals. 

History and Technical Notes:
The 911 Turbos from 1976-92 and 2001- onwards were all equipped with check valves to counter this problem but the Porsche factory did not originally equip the 993 Turbo models with components to stop oil flow to the turbochargers on shut off.

This problem was briefly addressed on the last editions of the 993 GT2 Evo models, but strangely not on the 993 Turbo road models.  Instead, Porsche issued technical bulletins instructing dealer technicians to install specific oil filters to a specific torque value – which does not solve the problem. 

The TurboKraft 993 Turbocharger Oil Supply Line System:
We have developed this package to be a completely bolt-in, high-reliablilty replacement for the original turbocharger oil feed lines. 
Installation involves simply replacing the original equipment oil line assemblies leading from the engine to the turbochargers. 
This kit is a must-do for all street and motorsport models, or for vehicles fitting new OEM turbochargers. 
Works with all K16 turbochargers, GT2 K24s, and hybrids, i.e. GT1, K16/16G, etc.
If your 993 Turbo has non-factory Borg Warner/KKK turbochargers, please contact us for supplemental parts advice.

Complete Package Set Includes:
:  Check valve set - Stainless steel and billet aluminum, designed for high temperature with low crack pressure.  Lifetime warranty.
  100% made in the USA.
:  Oil filter screen set - Fine mesh internal check valve screens inhibit debris from entering the turbochargers.
:  Adapter fittings with seal rings 
:  Teflon oil line set - Stainless steel braided over Teflon with crimped fittings, pressure tested to DOT standards.
:  Detailed fitting instructions
:  Warranty