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.