Yes, generally in the TD5 rev counter kit you get a female pin to go in the relevant hole in the ECU plug, plus a diagram of which bit of the ECU plug it needs to go in. Aside from that, if I remember correctly, you need an ignition switched live feed, and a live feed that comes on with the lights, to make its internal light work. Oh, and an earth, as it'll probably end up being mounted in a plastic surround and won't be able to do so through its casing. So they're not too hard to wire up.
It's just not that exciting watching it hover between 1000 and 2000 most of the time in town and then go up to about 3000 on the motorway. I don't want to sound too negative. It's a little bit of fun, but not what you might call a 'peak experience'.