ok i have a Msi 945gm1 board with a realtek onboard sound card it has 3 input/output that are software configurable so i can use 2,4, or 5.1 sound but i need to have a line in for hdradio and sirius. it has a cd in connection but i would have to splice cable. should i get a new sound card that has all the input i need or work with this?

also with the sub/center output do i need to split the center from the sub output? will it cause problems if i just hook it up to the subs with a rca cable?