Pontiac Grand Prix GT 3800 Series 3.

My daughter went and had her steering gear leak checked out. Mechanic said passenger side seal was leaking, steering gear mount bushings were shot, and would probably be better to just replace the steering gear. I haven't taken a look yet, but need some advice. How hard is it to change the seal and bushings? If it is better to change the steering gear, how do I know which one to get? When I looked it up on O'Reillys site, I see variable or non-variable effort steering (N40,NV7,NV8), magnasteer or non-magnasteer. O'Reillys sell Cardone, Autozone sells Durlalast, Napa sells its own brand. Just looking for some direction here. I will try to do this work myself. Thanks.