Replacing the water pump is not a bad idea but I personally would not do it if it was not leaking. I see these pumps routinely go 200K and further. I would replace all of the pullies and tensioners. The cam seals I would not bother with unless they were leaking and if you do them do not stuff in anything other than factory Volvo seals. In the past 10 years of running my own shop I have used aftermarket seals (Elrings) 3 times and 3 out of 3 have leaked within 6 months. I tried them when I first opened the doors 10 years ago, again about a year ago to see if it was just a fluke, and once more on my own car about the same time as the second set I installed. I got to change out the customer pay set and have yet to address mine and they are leaking pretty bad. You might want to take a look at the engine mount that is mounted right down by the crank pulley, you will be in that area and they do go bad from time to time. They are another one of those "you get what you pay for" kind of things. You can buy a cheap crappy one and it will last a while but usually not that long or you can spend your money on the correct factory part and enjoy it much longer. If you do need that mount and you can find one made by Corteco or Boge then you can pretty much buy them with confidence as they are the typical manufacturer of those components for Volvo.

Mark