They are matched for a dual channel system. They MAY work in a quad channel system but there is no guarantee. I suggest that you find a set of RAM that has been picked and constructed for a quad channel system.
Page 60 shows the absolute min/max voltages, these were never released for SB and haven't been released for IB however I don't see them being much different for SB. Oddly enough they have VCore pegged at 1.4 max but a lot of people run over it.
The 1.5V memory recommendation comes only from JEDEC specifications (page 61), not from Intel's internal engineering which supports up to 1.85V
I've heard conflicting reports about going over 1.5V voiding warranty. There are a number of reports of chats with Intel reps claiming that it does, yet here's one transcript that claims it doesn't and that a warranty replacement would be issued so long as there's no physical damage to the CPU