Front upper strunt mount replacement...1991 RS

Are the upper strut mounts something that I can easily change? I just bought the car from somebody, and the left upper mount is bent? Can I replace it without jacking up the car and without removing the strut itself? Is it as simple as the three nuts for the mount and the one nut for the strut? And then of coarse, take it in to get aligned?

Also does it matter whether the strut mounts are new or used, and do I have to replace them in pairs?

Any suggestions?

Thanx!

mine were all messed up and i changed them in about 1 hour.i didnt use a jack or anything if you can fit under the front thats the way to do it. thats the way i did it. and just turn the steering wheel to get to each side.