[W126 Coupe] control arm and motor mount replacement?

[Shayegan, Richard]

Just got back from the tech (boy what a difference fresh brake fluid makes. Now my pedal actually stops the car without having to go past the half way mark). I always have him look things over, and here are two things he found: left rear control arm is rusted about half way through (this started about 12 years ago...and at that time the dealership my dad used to take the car to told us how we needed to change it ASAP or face certain destruction) and the motor mounts are broken. He said the control arm is at the point where I might want to start looking for a good used arm to stick in and that while the motor mounts are broken, it doesn't seem to bother anything (runs like butter) so I shouldn't bother replacing them. Are motor mounts a big deal to replace? How about the control arm? I'm moderately able, but I don't have things like an engine lift and such, and I can't lift the car in the garage unless I use ramps because it isn't wide enough to get my jack in place.
Thanks,
Richard