I don't think the efx600 is enough on it's own, especially when you consider that the flow rate given isn't including all of the filter media that goes in it, which slows it down further.
Actually... for a change, this flow rate *is* inclusive of the media being in place.. was one of the stipulations MA made when the packaging was designed
The EFX 400 would be absolute minimum for the tank but if stocked low, it would work... the EFX600 would be more than adequate. More filtration or powerheads can be added later on if needed when fully stocked or planted etc....
Alternatively there is the TetraTec EX1200...
I dont think the FX5 would fit in the cabinet, its monstrously huge as filters go!