Need help with RC55i and RC60I speaker matching

Irondawg
Irondawg Posts: 2
edited February 2012 in Speakers
I just moved into a house that kindly left their RC55i spreakers in the front and RC60i in the rear. What I don't have is a center and sub.

I'm no kind of audio guru but had always heard it's best to match manufacturer for speakers. I think the matches for these speaker are CS1 or CS2 for the center channel - is that correct?

And what about a sub - recommendations there?

And while I'm here, I currently have a HK 235 receiver but it doesn't have HDMI hookups - is it worth the money to invest in a new receiver?