Yup, I am running just water injection on my truck for the same reason. However WI and intercoolers do have their differences. An intercooler does a great job of cooling the charged are before entering the combustion chamber and will net a more dense oxygen content. While the WI takes up some space within the chamber that would otherwise have been filled with oxygen. The WI does have other benefits that the Intercooler doesn't have as well, it keeps EGTs under control a little better and it keeps your combustion chamber a little cleaner(kind of like a steam bath). It also helps with a more efficient burn wich lowers NOX emissions. The main thing is it "effectively" increases your octane rating because it aids pre-detonation to help with engine pinging. There might be other differences, but those are the ones that stand out the most.

 

I run a smaller pulley on my truck and I think I saw a smaller pulley for the jackson SC I was looking at. You can always have it fab-ed up. However expect higher EGTs, going into boost quicker(more gas consumption), and possibly exceeding SC rpm ratings. I would say WI and/or intercooler is a must. And not recommended for stock internals.

 

I would say keep it under 6psi of boost and you should be fine, unless you drive with your foot to the floor all the time. If that is not enough power for you and you want to increase boost levels, internal work should be considered.