I have the JWT POP/JWT ECU comb...I think it adds a good amount of power...they say 10HP...maybe...
The POP sounds really good...got that nice sucking sound and pulls in the upper RPM ranges.
I was thinking about putting a CAI on, however, I was really worried about hydro-lock, so I stuck with the POP.
I have noticed though (I Live in FL) that on really hot days...that POP is sucking some realllly hot air under the hood. When it cools off at night and into the winter months, I can tell a difference because the air is...well somewhat denser.
However, there was a discussion not too long ago about how the CAI actaully makes the power. Its not really too much from the difference in intake temperature, but rather the resonating effect of the long tube.
Keep in mind that the POP is probably a little easier to install...with the CAI (I think HS)??? you have to have a smaller-than-stock battery...guys with it out there correct me if im wrong. Also I'm not sure if they make one for the High port engine that we have on the 93.5 and prior...the intake piping is really low down there...itd be interesting to see.