Yeah mate, the 235 khumos where just not up to the task, I usually run 265 Dunlop R but I got the khumos for free, the car is going in to suspension warehouse for some bushes and adjustable caster arms, while its there I'll get then to give it a good hard look over.
Also I'm in the market for some 255/40 17 R medium/hard comp tyres, not sure on what brand though, price will factor in so whatever tire rack has in that size in a motorsport tyre maybe.
I want one of those camera thingies you got though, it's awesome, what was the brand and model again ?