if you want hqi, get a pfo hqi ballast unless you're not concerned that the output of the IC ballast is less than the m80. if you're thinking of an icecap ballast because of it's "efficiency", it comes at the compromise of output from the bulbs... There are also some bulbs that the icecap won't fire. someone else might provide us with a list of them.
on sale you get the icecaps around $320 for 2, or the PFO HQI ballast is $329. so if you're after real light output, pfo is the way to go!