The VG33 plenum has a larger intake opening to go with the larger throttle body, but they're otherwise pretty much the same other than various vacuum ports and such. However, the VG30 MAF is the real bottleneck in the system, quite a bit more restrictive than the throttle body, should see something decent from swapping the MAF. The VG33 and VG30 MAF are 3-wire units, and have similar, somewhat overlapping, voltages, so should be compatible. We'll know soon enough, though this weekend is going to be too damned cold to monkey around with it...