I just converted my mini Z head into a combo with the 1X10 Z speaker/conversion cab with the Red Fang alnico speaker.
I was previously running it through a Z 1x12 with the Celestion V 30. I think it sounds a whole lot better now through the alnico speaker, The difference is astounding and I would never go back. Is well worth the cost and buying it in the Z cab already is surely the way to go as otherwise it's a really expensive speaker. I also added a JJ gold pin 12ax7 a few days after the convert and it seemd to make the amp more complex and detailed sounding.
I needed it to be a smaller combo so it would fit in my truck seat to go to band practice. The conversion exceed my expectations and my favorite amp is now really the sound I was after. This is about the best amp ever built and I love mine.
So even if you cant do the conversion I highly reccomend the red fang 10" cab. I don't think much could be done to improve upon it.
It really is good on the mini and makes past 3 oclock much, much more fluid feeling on the amp.
I'm new here by the way, so I'll get some pics up real soon.
Oh and to answer your question, the standard mini speaker is an eminence red coat ramrod- the upgrade or deluxe model has the red fang, I'd reccomend you get the red fang if possible. I just did a lot of research on this a few weeks ago, The doc is offering the speaker at an incredible price included in his cab.
www.humbuckermusic.com/drz1xspcabin5.html This is the one I used by the way, and I hope links are allowed, thanks.