rkneeshaw, it's the wheel offset that's causing the problem. When your wheels were pushed out by 10mm you've changed the scrub radius of your front geometry. It went from slight negative SR value( factory setting ) to slight positive SR. That will greatly increase the sensitivity to the road crowning and any imperfections. I bet you feel that there is more feedback through your steering wheel when you are driving with these wheels.
To a degree this is good thing as you can 'feel' more of what the front wheels are doing. But in the long run, it will be tiring/fatiguing to drive for distance. Another side effect is during a tire blow-out the steering will be pulled to the side of the tire failure instead of more or less neutral pull of factory SR setting.
