Unfortunately, the GAU-8A Avenger would not be a feasible size weapon to mount on an IFV.
The weight of fire from the GAU-8A is enough to stall the multi-ton A-10 if fired for more than 3-4 seconds, so you can imagine an IFV trying to keep pointing in the right direction while firing bursts...
Also, the size of the weapon itself would not permit turret mounting, while also eliminating the IFV's troop carrying abilities and having to use fitted stabilisers to be deployed before firing (again, the "taking too long to setup" factor).
There are also several other factors involved, which I will only cover if required (related to the weapons main purpose, intended targets, type of vehicle its mounted on, etc).
So while it would certainly be impressive, its a little too large a calibre and impractical for an IFV.
Maybe as a permanent system built into a bunker, but when it comes to vehicle mounts, not on anything other than an A-10 I'm afraid.