Warren,
You will make more power by using WMI vs just a new intercooler. A larger intercooler might give a little more power, but really only in situations where the stock one would otherwise be getting heatsoaked. That said, it depends on what your goals are... If you're doing some aggressive, consistent track driving, then a larger,
aftermarket intercooler might be beneficial. But if you're just on the street, it may not be that helpful.
As far as just using water, vs a water/meth mixture, you potentially can still get some gains by just using water, as the JB4 can take advantage of the cooler combustion by increasing boost. You will want to use BMS's smallest nozzle if you do so (#5 I think). Though, generally speaking, the more methanol you use, the more power you can get.
I have not seen any evidence of an
aftermarket BOV improving boost recovery in our cars, or responding any faster than the OEM diverter valves. Keep in mind that your engine should not be releasing boost in-between shifts, so it's a non-factor for shifting.
IMO, the *only* reason to get one is for the noise. Literally nothing else.
