There is a mislabeling of price for Mac mini Server with 8GB RAM in Taiwan. So many units of the mini is purchased by regular consumer. Since the server version of the OS does not have the Chinese language interface, people want to install the consumer version of the OS. There are rumors that consumer version of the OS would not be able to install on the mini server. Is that just a rumor or is that real? Has anybody ever tried it?
The Mac mini runs the regular version of Mac OS X just fine however it is more tricky installing normal Mac OS X on the server because of the lack of a built-in DVD drive and how recent the model has been released. A normal retail Mac OS X Snow Leopard DVD will not reliably boot the Mac mini because it does not contain the drivers for all the new hardware in the Mac mini. There is also additionally a separate updater for 10.6.4 for this version of Mac minis. (This information is correct as of 10.6.4, once 10.6.5 comes out this will most likely all change, especially if they have a newer version of the retail DVD available, however 10.6.4 may be able to boot the Mac mini – the separate updater for 10.6.4 may required)
For reference, the main difference between Mac OS X Server and Mac OS X Client is additional software packages are installed. (eg. Calendar Server, Address Book Server, and several others).
I haven’t tried this, but it would be very strange if you couldn’t install the consumer version of OS x on the mini. There’s not really a (big) hardware difference between a mini used as a server and the one used by consumers. The biggest difference is disk space and stuff like that, so there should be no reason why you couldn’t install OS X on it, since it’s more or less the same computer.