2.9 may sound fast but Road and Track tested the 2003 model (550 hp) at 3.4 seconds to 60 and if you read the article on Fast-autos.net, it says the Saleen engineers gave the 2004 S7 more power and a shorter 1st gear ratio so quicker accelaration is very possible but I would hesitate to believe 2.9 until I saw it tested by a magazine or reputable third party.
"It's the only car I've ever driven that'll spin the wheels at 200 mph."
-Mark Donohue, talking about the Penske 917/30 twin-turbo Porsche Can-Am car.