First of all welcome.
The 996S in US and Europe are different. Firstly the differences between the Euro S and US S are the HP. I'm affraid that the US S has same BHP as Bip (~116) and the Euro model is similar to SPS (124BhP)
But saying that the US S got Ohlins front (Euro got Showa) and I think some extra carbon like a front mud-guard and may be other parts.
The Euro S has 50mm exhaust as std - not sure what the US S has, probably 50mm so long as it met the strict US emissions laws.
The Euro S came with both mono and biposto versions - poss US S only mono? But if mono probably has aluminum rear subframe (less weight)
Euro S has SPS engine (less Ti Con rods 124Bhp), Ti Nitride Showa forks and maybe slightly uprated brakes (steel brake lines), Ohlins rear shock. No weight difference.
Good choice either way
[Edited on 21-3-2004 by ziggi]