handling

Took car to the shop and was told that the brake master cylinder needed to be replaced. Already had the brakes done and then told me this... Kind of felt a rip off coming but brake fluid seems to be leaking slowly and pedal shakes when trying to brake... Is it easy to replace master cylinder?

I just bought a 2008 G5 with 53000 miles. I love the looks and find the interior very comfortable. I would like to improve the handling. Does anyone know of a way to tighten the steering up a bit? Also, what's the best way to stiffen up the suspension? Thanks.