CV Axle Assembly

I have a 92 Lesabre with a vibration when the wheel is turned to about 1-2 o'clock. I have repalced motor mounts, tie rods, and stablizer bar bushings. It's been an issue since I bought the car with 107k miles. I now have 130k and it's a bit worse.

I figure I only have hub assemble and cv joints left.

I have found what looks to be an assebly of both inner and outer cv joints. Is this a better repair option than trying to replace just the outer cv joint?
http://www.autopartswarehouse.com/search/?Ne=28&N=9808+1585+4294966981+5637

Not sure if this means anything but I notice a loud knock when I put the car in Reverse and the wheels catch up with the drive shaft....could be nothing but I thought I'd mention it.

Thanks

Another piece of the puzzle.

I don't know if this is related but I hear a loud knock when I move the car in reverse.

Are drive axles difficult to replace or just time consuming?

Thanks, for any advice.