I've searched for the last couple of days.. probably not hard enough lol

I've had my 2005 S4, for a week now, loving the car but with the instrument panel the rev counter, and the fuel gauges sometimes have a mind of there own. Been down the stealer and they done their "Tests!" and say i need a new cluster. I've found one at a breaker for an identical car (same spec/auto box/year etc) the mileage is a few thousand km more than mine but I can live with that.

Is it just remove the old cluster and put the new one in.. or do I need the code for the car the cluster is coming out of? if i don't have the code can it be re-programmed with VAGCOM?

thanks