Which would you chose? (Filter dilema)

I'm considering going with a marineland bio-wheel filter. I currently have a tank with fish (with a decent working filter), but in just browsing these boards I have seen good things written about bio-wheels about their performance and reliability. Now I'm just deciding which model to get, because I think in the long run this will be a more efficient and reliable purchase (plus I can have my old filter as emergency backup).

I currently have a 29-30gallon tank. Should I go with penguin model 150 up to 30 gal. or the model #200 up to 50 gal? I would like the most filtration (obviously!), but thought that maybe 50 would create too much turbulance and upset my fish. Also those model #'s are from petco....and I notice they are different from marineland direct website info (just in case that was throwing anyone off).

Yeah those were my thoughts...I'll try finding something around here about modifying the flow. I'm not a fan of minimal filtering as well, which is why I wanted to change the filter (this tank set up I have, minus the tank and ornaments were given to me). I was thinking the 50 just was worried that my small barbs would be angry with me if it caused too much disturbance in their tank.