AtDarrylB kindly fitted one of these for me (as I have very little technical ability) and I have to say it is one of the best £20 mods you could do.
I have an early 2.0 SRi and so it has cable throttle, not fly by wire. Before it was fitted you could rev the engine by pulling the cable (leaning over engine) and could see the block move about 1-2 centimetres as the engine rev'ed. With the mount fitted the engine doesn't move hardly at all.
On the road it makes a huge difference - noticeably better acceleration/gear changes. For anyone that hasn't done this it is def worth it - oh and it is a 5 min job - even for a wally like me. Now having seen Darryl do it, I reckon I could do it in under 10 mins!! (Darryl did it on mine in less than 10 mins easy)