I've had spacers (10F, 25R)since the day I drove off the dealer lot. I've had Jamie's race blocks since about 6 months later. Prior to the race blocks I had done an alignment and added shims for camber.
Couldn't be happier. 32,000kms and I can drive the car with one finger whenever I want to. Several track miles, no apparent abnormal wear. It's awesome. Performs amazing. Looks amazing too.
The primary reason manufacturers don't push the wheels out to the edges of the car is to save your paint, minimize the chance of your wheels throwing rocks at other cars, and to minimize rooster tails in the rain which impact other drivers.