I have the PC360 as well and a Xonar DGX driving them. The amp makes a world of difference for this headset. They get punchier, more noticeable low end, smoother mids, and clearer highs. Overall they are better sounding, although they didn't sound bad to begin with.
The spacial positioning is fine on this headset on stereo, but if you would like virtual surround, the DGX offers Dolby Headphone (5.1) or 7.1 virtual surround. It also has a 10-band EQ that you can mess with if you choose to.