That is a big chunk of money to spend on a 16 year old car, but for a good shop that knows these cars, I think that is reasonable and sounds like a good refresh of the car that will keep it reliable for a while. While they are doing that I would also consider adding in the water pump and
chain pads on the variocam.
If you are equipped and willing, some of that is not bad as a DIY and we can guide you through. On the other hand, I just asked a shop to go ahead and replace the front and rear main seals on one of my '99s. Even though I am capable of doing it myself, I just don't have time to get to it and have put it off too long. I'm paying $112/hr labor. The 2 seals will cost about $20 and I'm having them do the engine mount which is $162 for the part. By the time it's done I'm expecting to pay about $1,750 to install under $200 of parts. ...and I'm glad to have the job off of my project list.