I have:
1. Volvo Hole Punching Tool: [9814069] - about £15 at dealers
2. Volvo Activator: [8637076] - about £25 at dealers
I used these only once when fitting parking sensors on my S60. Fitting the sensors yourself is very easy and you save a lot of money!
The whole diameter punched with this kit is 31mm.
These will probably work with most of volvo cars but I'm not sure. Check here
http://vccs.volvocars.se/accessories/ii/search.aspx what tools are required to install the sensors on your car.
It's almost new.
I want £23 for it including postage.