Has anyone done the APR stage II and pulley modification on their S5? Supposedly, this increases HP by as much as 140 HP without ruining the car's around-town manners. I'd love to maximize the performance of the car, but I don't want to make it a purely racing/rally beast. For the investment, this seems like a really great tuning option. The only thing I would add would be a larger intercooler. I'm also trying to stay away from modding the suspension and braking. Any thoughts?