Please mind I've only had the car for half a week
I can pretty much only compare it to my old severely modded Pug 206.
The 206 seemed faster in the city. I think it's a combination of the 1G-FE engines heritage (developed in the 70's) and the low gearing of the 6-speed. The gearbox could well have been geared higher. On the motorway, I miss an overdrive gear or something.
On the motorway, from 80 and up the 206 felt like it *wanted* to go faster, not that it had that much power though. The IS200 gives more of a push in the back type of feeling which is very different and it clearly has more power. In this aspect it's a very nice engine.
Oh, and I love the sound of 6 cylinders ^_^ Really adds to that "I'm driving a really nice car" feeling.
Significantly reduced wind and tyre noise, although it could definitely be better. 3.5-4 stars out of 5.
Roadholding ability is pretty good, but it's hard to compare as the pug had a full race suspension and semi-race seats. The second IS200 I tried (I bought the third) was extremely floaty though. A bit like an american luxury car, but still transmitting the bumps in the road. Took half a second to react to steering input. Mine's fine though :)