I have seen many Mustangs with 550 rwhp and hit 10s. However, most Lexus and Toyota with 700 rwhp hits 11s. Here is one example http://youtube.com/watch?v=zW6DzpCvqbs
I know the video is just an example but it's a manual for a start, (just lost at least a second down the quarter) and there's no way its got 700hp at the wheels.
If it does, he's just cruz'ing
My car would very likely do a 10 easy with slicks with only 430rwhp as did an 11.7, and would have done an 11.5 without a missed gear, on street tyres.
With the current 500+rwhp would do a 10 easy on street tyres.
Alot can come down to practise too....not just a matter of stomping the peddle. Not only about hp either as i'm sure you're aware.