Mako,
I don't work for Dodge, so I can't say I know anything official. I HAVE "worked" all the folks I know for info on the SRT. What I have *heard* (from folks who I trust to have genuine information) is that the SRT has been easily making 525hp in testing. I've also heard that a very restrictive exhaust system is being used on the car which limits the HP rather severely.
Don't forget that numbers never tell the whole story, because we can never take all the variables into account. The GTS is "only" 50hp more than the early RT's, but it runs a good .7-.8 and 7-8mph faster in the 1/4 mile. Yeah, there are old RT's in the low 12's, but there's also GTS's in the mid 11's. Likewise, the Z06 was "only" 35hp more than the C5 in '01, but it was a good .7-.8 second quicker in 1/4 acceleration.
The SRT is a totally new car... new chassis, new body, new engine, new suspension, new tires, new interior, new everything. It's not a reworking of an earlier design, it's a new design. Who would have guessed the Z06 would be so much quicker than the C5 with only 35hp more? Who would have guessed the GTS would so outperform an old RT with only 50hp more? We're talking a good 50 or 75hp (depending on which #'s you believe) and 100-200lbs less weight (we'll see when it rolls out). I am thinking that we will get a TON of performance - more than the numbers would suggest. I've already heard the #'s were alot better than expected. I'm expecting we'll see SRT's will run 11.8's at 123 stock, just like most GTS's run 12.2's at 118. I bet some of the better drivers will get 11.3's or better at 125mph, just like better drivers get 11.6's and 120 trap speeds in GTS's.