Dear MacRumours, This question has confused for some time. The interwebs claims the upgrade disc does NOT feature the "erase and install" option, and will ONLY upgrade your current Leopard installation WITH files to SL. This would mean, that we had to format Leopard, and then install SL to get a clean install. Is this true? I ordered the box set even though I have leopard, because most mac sites claim the above mentioned feature is long gone. so what is the CORRECT answer?