I see several people who either comment "choose your mobo carefully to fit IO and all PCI slots" in a G4 case. Plus pwalth21 who did a mod 4 years ago and has an M-ATX board that fit without modification. OR maybe he's sacrificing some audio ports? No specs I see for any motherboard list things like distance from the near edge of IO to the first PCI slot. How do you get these measurements without having the board in your hand?