I have just ordered an IS300H following an extended test. Coming from a series of turbocharged cars - most recently A Saab 95- Aero (250BHP) and a 9-3 TTiD (180BHP) diesel Aero I was concerned about overtaking and hills but it actually drove in quite a similar manner - but with rather less drama - then the Saabs. There is power available whenever you prod the accelerator and if in a hurry you can use the 'Sport' mode.
No problem with space - I am 6ft2 and always lower the seat as far as possible in every car I drive. Very comfy and as you can see above I'm used to excellent seats.
MPG on my 150-mile test was just shy of 50. I didn't get fully to grips with the satnav graphics, but it all seems endlessly adjustable.
Roll on April when my IS arrives!