I assisted my Father in Law with the valve stem seals about 6 years ago. I wouldn't have done it on my own then, but I would probably give it a shot now - I'd say I'm about medium skill level for a non professional.

He had a Mercedes valve spring compressor that made the job straight forward. I don't know if a regular valve spring compressor will work, but you will need one. It's at the top of this pic:



Sorry, this is one of the only pics I have of it and I didn't take any pics with it in use. I don't know the part number either.

Also, I don't remember how we kept the valves from dropping into the cylinders when we did this, but we probably used an air compressor.

If you get the valve spring compressor, I'd say go for it. Just make sure you review the instructions, be patient, take it slow, and don't plan on needing the car for a few days in case you run into problems.