Interesting thread
I have the KW v2 kit on my Leon, got the ARB & Pollybushes done all at the same time and as you say the car feels a lot more sure-footed when in hi-speed corners, you should notice it even more when you get around to the ARB's.
Very interesting comments on the tyres as well... (i'm running 225/40/18) i had the Avon ZZ3 and thought that they were OK in the wet (nothing great, but OK) but terrable in the dry when pushing hard. Now have the Falken 452 and they are far better in the dry, but a bit scary if you hit standing water.
I find that the Avon's dont give any feedback as to when they are about to lose grip, where the Falken & before that my Kohmo (712 i think - not sure) i can hear & then get a slight change in the feedback from the steering wheel just before they lose grip.
On track the Avon's are total rubish, as they have a lot of tread-blocks they overheat too quickly and the grip goes, the Falkens did not (would take 8 hards laps of Knockhill to get them going off).
Also the car looks great when lowered just that wee bit, i would say you could go a bit lower (10/15mm) on the back just to set it off, but thats personal choice
Dave