From a post I made a few days back....comes the experts:

Dear 001,



My Porsche sources say the 997(2005-2007) update will only apply to the non-turbo models. The Turbos will remain on the 996 platform.



Then after a couple years they will come out on the 998 platform (2007-2008). The lights on the 998 will be almost identical to the Carrera GT lights, while the 997 will have retro look lights. Engine wise, the 997 will have a few more horses, but the 998 will have Cayenne derived v8 engines tunes to 400hp stock and 500hp in turbo form. The interior on the 997 is derived from the cayenne and will continue unchanged on the 998.



The double clutch gearbox will be available on the 997 and 998. 19 inch wheels will be available on 997 with 18 inch as standard. Also the 997/998 are going to have more standard features than present.



Prices are expected to be almost the same. However the 998 v8 will be significantly more. Also the "big heads" at Porsche have not yet decided whether to only have the flat 6 on the Boxster and have the Carrera only run the V8, or have the Carrera running the V8 and flat 6 stretched to clost to 4.0L.



Thats what I know for sure, more to come...



997 Update!



Seems like this is the suspected timing:

2004 late: C2 and C2S Coupe

2005: C2S Cab and C4S Coupe

2006: C4S Cab (400hp), GT3 and Turbo

2007: GT2

2008: 998