2005 suburban steering, handling and braking issues

[Dude68]

I have an '05 chevy suburban 1500 2wd with the Z71 package. I am the only owner. It has low miles but drives like it is a super high mileage abused vehicle. It is my wife's daily driver. Her commute to work is 8 miles round trip. I do not want to buy a new truck. I have these problems and would like some feedback.
1. Steering has a lot of play. Mechanic said I was used to my rack and pinion that's in my '08 Silverado and there was nothing wrong. You can move the steering wheel 1 inch side to side without any wheel movement. I seen some stuff out there on the Internet about replacing sphere shafts and stuff. any suggestions?
2. Are there any brake upgrades that can be done to improve braking on 4 wheel disc systems that are common on this year suburban?
3. My dash is fading. The paint on the radio buttons is chipping.
4. What's the best place to purchase leather seat covers from?