I have some questions and hope someone can help.

I am changing the speedo cluster on my 2007 mazda 6i (I messed up my cluster soldering leds) First question, will a 2005 EL cluster on ebay, work in my car? I do not have the EL gauge, but I figured connections are same, it is just lighting. If that does not work, will a regular 2005 cluster work? Or do I need to get another 2007 cluster? Next question, when I change the cluster, will the car work as normal. (I know the milage needs updated) but what about fuctioning as plug and play? Will imoblizer block new cluster? I took my cluster out, and drove the car. So I don't see how a new cluster would stop the car, but I could be wrong. Hope someone can answer this for me. Thanks!