Any lancard that is recognized once pf is installed should work. i am pretty sure the above lancard works. as far as virtualization, if you are using the older version of pfsense, one core is enough since it does not recognize multi-threads but later versions of pf does utilizes multi threading and as a general rule you should only use up to the max number of physical cores ie. if you run quadcores, max is 4, do not count the hypercores. as far as memory utilization, it all depends also on the other programs you will be running along with it, you might want to start low like 2gig (with enough left for the other programs to use), then adjust/increase later on. My experience is that the more RAM the better