No you can't have both integrated and pcie. No, a tuner card and a integrated video would not boost each other. No coaxial etc., no 5.1...
Looking for comments from experienced users -
 Can the integrated video work simultaneously with a PCIe graphics card? with a PCI graphics card?
 Does the ATI integrated video boost performance with an ATI tuner card?
 Does the system have S/PDIF outputs? Coax? Optical?
 Does the system have 5.1 audio analog outputs? (in addition to mic in, line in, line out)