The X3 head is engaged..a little birthing help please

 Ah, forgive my metaphor!
I'm a UK Cakewalker who has been so since Pro Audio 9 then Sonar 2, then 6PE, labouring with my old diesel and clockwork XP pc with M-Audio Delta 66 PCI card. I've been "making do and mend" on my 10 year old Evesham(remember them?) Axis but it's now time to retire the old thing.
 I confess I HAD been working towards a Pro Tools system until realising that I'd have to sell many people's grandmothers and body-parts and then still be wondering where to get 64-bit plugs and instruments from.
Mercifully my chum slapped across the face and pointed me at X3..and I have to say even at this stage that I'm astonished that a DAW this complete can be grabbed for so little cash, so I'm thus at The Crossroads Of Everything, as I'm now just about ready.
  I wonder if some wise heads here would kindly fill in some gaps for me please...?
1. I've added my X3 and "hardcopy" DVD set to cart. I intend to download my X3PE upgrade(from 6PE) on my old XP machine, to do my main install on a new W7 or 8 one. My daft question: do I in fact await delivery of the DVD, load that on my new W7 pc, then give it the reg/serial number that accompanies my download? Won't I thus have a massive downloaded version "spare"..or have I misunderstood? CW support, who got back to me very quickly, reminded me as I knew that I can install an additional copy..but is this the same thing?
2. I see that in the past few years PCI cards have either melted away or become the domain of "high end"; for various reasons and luddite prejudice I intend to go for firewire(Focusrite Sapphire Pro 14 or Motu 4Pre...I'll only need 2 pairs of ins and 2-3 pairs of outs for different reference/monitoring configs) with decent AD/DA conversion [my midi's covered].   Am I right that I'll be best served with a motherboard that does firewire "native" as opposed to "bridged"? And, er...are there any chips that do not play nicely with Texas Instruments firewire cards in terms of X3? I don't really need pointing towards any one of the interfaces I've mentioned, yet if anyone has experienced "issues" above and beyond the normal with X3, by all means say.
3. I'm at the head-scratching stage with configuring a machine...(am between any of Scan, Blackhawk, or even a gaming-spec one from Palicomp or Dino pc at present). My biggest unknown is motherboards..despite much research I remain uneducated about "good" ones, though I think I'm set with general spec of the rest of the machine: an i7 quad(no overclocking but I gather they're "self-boosting" to turbo), W7 or 8 Pro, 16 or 32GB RAM, a 2GB video card(nVidia I presume on an Intel board, or am I mistaken?); a slack handful of USB2/3 on different buses or discrete cards; 120GB SSD, 2 SATAIII 2TB drives at 7200rpm.
If there's anything glaring I've omitted or if there's any howlers I've dropped, I'd be grateful if some kind sould could point it out.
  Other than that, I have to say this process looks a darn sight easier than when I was trying to get my brain around Avid: to be honest I was cacking myself seeing the price going past 3 grand with no assurance all would be hunky dory. I wimped out well before I realised I might be swinging in the wind with PT11 and no instruments to play for a while.

Zig
 Ah, forgive my metaphor!
I'm a UK Cakewalker who has been so since Pro Audio 9 then Sonar 2, then 6PE, labouring with my old diesel and clockwork XP pc with M-Audio Delta 66 PCI card. I've been "making do and mend" on my 10 year old Evesham(remember them?) Axis but it's now time to retire the old thing.
 I confess I HAD been working towards a Pro Tools system until realising that I'd have to sell many people's grandmothers and body-parts and then still be wondering where to get 64-bit plugs and instruments from.
Mercifully my chum slapped across the face and pointed me at X3..and I have to say even at this stage that I'm astonished that a DAW this complete can be grabbed for so little cash, so I'm thus at The Crossroads Of Everything, as I'm now just about ready.
  I wonder if some wise heads here would kindly fill in some gaps for me please...?
1. I've added my X3 and "hardcopy" DVD set to cart. I intend to download my X3PE upgrade(from 6PE) on my old XP machine, to do my main install on a new W7 or 8 one. My daft question: do I in fact await delivery of the DVD, load that on my new W7 pc, then give it the reg/serial number that accompanies my download? Won't I thus have a massive downloaded version "spare"..or have I misunderstood? CW support, who got back to me very quickly, reminded me as I knew that I can install an additional copy..but is this the same thing?
2. I see that in the past few years PCI cards have either melted away or become the domain of "high end"; for various reasons and luddite prejudice I intend to go for firewire(Focusrite Sapphire Pro 14 or Motu 4Pre...I'll only need 2 pairs of ins and 2-3 pairs of outs for different reference/monitoring configs) with decent AD/DA conversion [my midi's covered].   Am I right that I'll be best served with a motherboard that does firewire "native" as opposed to "bridged"? And, er...are there any chips that do not play nicely with Texas Instruments firewire cards in terms of X3? I don't really need pointing towards any one of the interfaces I've mentioned, yet if anyone has experienced "issues" above and beyond the normal with X3, by all means say.
3. I'm at the head-scratching stage with configuring a machine...(am between any of Scan, Blackhawk, or even a gaming-spec one from Palicomp or Dino pc at present). My biggest unknown is motherboards..despite much research I remain uneducated about "good" ones, though I think I'm set with general spec of the rest of the machine: an i7 quad(no overclocking but I gather they're "self-boosting" to turbo), W7 or 8 Pro, 16 or 32GB RAM, a 2GB video card(nVidia I presume on an Intel board, or am I mistaken?); a slack handful of USB2/3 on different buses or discrete cards; 120GB SSD, 2 SATAIII 2TB drives at 7200rpm.
If there's anything glaring I've omitted or if there's any howlers I've dropped, I'd be grateful if some kind sould could point it out.
  Other than that, I have to say this process looks a darn sight easier than when I was trying to get my brain around Avid: to be honest I was cacking myself seeing the price going past 3 grand with no assurance all would be hunky dory. I wimped out well before I realised I might be swinging in the wind with PT11 and no instruments to play for a while.

http://www.soundonsound.com/forum/showflat.php?Cat=&Board=PCMus&Number=721978&page=0&view=collapsed&sb=5&o=365&fpart=3 might be some help - i agree Scan is prob best in UK at mo for audio pc - one of their tech guys Pete Kaine posts regularly on the SoS forums so if you post there he and others will generally give you some helpful advice. 
don't rule out USB either for an interface - FW is pretty much a dying interface - some great USB models out there from RME, MOTU, Roland etc...