IMO it is as good as an air filter for the money. £20 ish and the sound in the car is great. I know people have mentioned having vibration problems, but to be honest I haven't.
There are a few threads on how to replace the bush. I did mine in under half an hour last week.
1.I placed a trolly jack under the engine to support the weight (don't jack it up or there is a possability of splitting CV's etc etc)
2.Undo the bolt with socket and spanner.
3.Used a blade to cut the majority of the bush inner out and used brut force to push it out
(but mine was really gone!) You may need to prise it out. The joining support brace to the firewall has enough movement to allow you access.
4.Insert the two halfs of the new one and lubricate and insert the new bolt shaft
5.Re-tighten nut and bolt.
6. Lower jack and all done.
It is as simple as it sounds, unless you replace the bush with an original Volvo one. I beleive you need some kind of press to do that.
Dave