How to audition used speakers???

One advantage of buying used is you can audition them in your home indefinitely (which IMO is the only legitimate audition), and if you decide you don't like them, just resell them and recoupe most/all of your investment. This is a little more difficult and risky with speakers that are large and hard to ship, so you need to be careful.

You should do your research so you're comfortable there's a hi likelihood that they will suit your room size, musical preferences, and will be compatible with other system components, etc. I would also try to locate speakers in closer proximity to home, so you can avoid shipping, or make sure the distance is short and cost is lower. If you find a local seller, they may also afford you an oppty to audition them in their home prior to purchase. Also, the archives contain many, many "speaker recommendation" threads that should be helpful if you search.
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As for good classic speakers, I think there are many, many. I'm not familiar with Spikas but see mention of them often here. You may want to spell out more of your parameters (ie budget, room size, musical preferences, and will be compatible with other system components, etc.) here to entice recommendations.

"Isn't buying speakers this way as good as rolling a die?"

Yes. Find a good dealer and work with him, unless you like rolling dice.

well, I just disagree. I DID buy a new set of speaker from a good dealer after spending a great deal of time auditioning them. When upgrade time came, I sold them for half my purchase price. Don't be mistaken, buying from a dealer IS a good option, but don't be confused about the economics. If you are careful, and thoughtful, you can significantly eliminate the risk of used, and end up with more speaker than if you buy new.