I've been wanting to replace the crap speaker that came with my HRD and I've looked at some videos/reviews/etc and finally made a decision based on this video:

I've decided to go with a Celestion. Then I came across this video: http://www.youtube.com/watch?v=aUx5JSjLzxQ

That is the speaker that comes with the HRD nowadays so I'm just going to get that. Now does the speaker have to be a certain ohms or anything? I want to make sure before I buy it. I found it on ebay pretty cheap:

If that's good then I'll get that. Can anybody clear that up for me?