vox pathfinder ministack - speakers replacement?

[rabbitw]

Hello,
I don't know that much about speakers, ohms etc. even though i've been playing guitar for a long time, oddly. So I have this question that maybe someone can help me with. I have a Vox Pathfinder ministack that I keep at home - separate 15w amp with 2X10 cab - i think the speakers are Celestions but i'm not sure of what type. 8 ohms. I really do like the sound of it for the most part. But I was wondering if it would be worthwhile to try replacing the speakers or even hooking it up to a different cab (i.e. vintage 30's 2X12)? Would it be louder at all? So much cooler sounding that it's a no-brainer to do it? And if I replaced the speakers, would I need two 16ohm speakers to end up with 8 ohms? Thanks for any help or advice you may have.