I would say yes, you'd get better results with a wet-dry/sump filter. I built my own in the past, so I don't have any recommendations for what's on the market now. You also have to look into an overflow box, assuming that you don't have built in overflows.
You could get another magnum 350 deluxe system, but i'd look into one of these if you don't go with a wet-dry, filter with protein skimmer and uv sterilizer.
Via Aqua
I've seen a different one too, but this is the only reference I've seen online so far.