[neurokinetik]

Well, those IRF510s don't even handle as much current as a IRF7389. You'd be better off just buying four IRF7389s and doing a 2x2 stack. Cost would be less once you figure in the price of the board and wire that you'd need for the IRF510. Plus you'd need to revise the circuit if you wanted to use all N Channel FETs. The circuit is designed for the complementary N and P channel setup. We don't know this for a fact yet, but the stock XMods FETs may actually handle as much current as the IRF7389, so in other words, the IRF510s will gain you nothing.

A Plasma Dash will fry a FET stack, and also keep in mind that the no-load current represents the absolute lowest current a motor will draw. As soon as you install it in a car, it goes up. Use a big pinion gear, it goes up even more. The first time you try to accelerate with that motor, those IRF510s will pop.