Is there a specific filler I can use? If it was just surface damage I would just sand it down, but unfortunately it seems like full on gouges were taken out of the Rims. The only was I could describe it is rash, but it almost looks like the last owner ran into a cheesy 1960s bad guy and they had a winner takes all drag race and the bad guy had spikes on his rims and ate into the Rims on the GXP.
I actually like the factory rim, though I feel that a Grey Car looks nicest with Black Rims and I don't want to just paint beat to hell rims, to make matters worse I know that the GXP Rims are hard to find locally.