If you get an Aquaclear wet/dry, get one rated higher than what your tank size is. The one that Nate had used to be mine, and I had it on a 75.
As far as increasing the flow rate of the filter, you can always drill out the holes in the drip plate to accommodate better flow. However, most pre-drilled 75's only have a 1" drain hole, in which case you are limited to the amount of flow you can run by that, more so than the drip plate.