Sorry if this has been covered a 100 times before but I have a few questions that hopefully somebody might be able to help with. 1) Does anybody have a simple guide to doing the upgrade? I have flashed/updated loads of hardware before from PC motherboards to Cisco MDS's but i'm new to Macs and don't want to break my new MP. 2) If I do the firmware upgrade can I keep using my W3520 on 5.1 until I find a hex core? 3) I think this has been covered but can I use an X series xeon in a single cpu MP? (on 4.1 and 5.1) 4) If I do the firmware update do I need to use 1333mz ram? (I assume this is dependent on the CPU) 5) I want to do a clean install on my MP as its second hand can I download 10.8 copy it to a memory stick and do a clean install on both 4.1 and 5.1? 6) Does the serial number change during the update?