Planning to downgrade a brand new macmini to 10.6. How do I recover to mavericks if things go wrong? I have a brand new macmini. It comes with mavericks and I haven't booted the machine yet. I know for certain that I will erase mavericks and install 10.6. However, if things go wrong, I would like to be able to reinstall mavericks. and restore the situation as it was as out of the shop. What do I have to do in order to achieve this ?
No you won't be able to install Snow Leopard, it's not compatible. 

But you'll be able to build app that a compatible with older OS X from XCode. But you won't be able to test it's behaviour on older platform from this mac. You'll need older macs.