From the lexus anouncement at the New York Auto Show 2005 in March, they said it should have "significantly more than 300 hp", world's first rear drive hybrid, MSRP expect around $55000, arriving next spring (2007).
I haven't heard anything since the announcement, though.
Well, the GS430 goes from 0-60 in 5.7sec, so I am expect the GS450h should be in low 5 secs. I am speculating, of course.
I can hardly wait for the real specs. I have the Rx400h (5000 miles on it) and LOVE it. 27 mpg mixed driving in a SUV without sacrifices (all luxury). Love the continuous variable transmission - super smooth, continuous power. I hope the GS450h also has it.