Why do you want to upgrade it? Are you maxing it out? Just do as Rich has partially said & fit some spray nozzles off your windscreen washer bottle, to a hobbs switch, off one of the vacuum / boost hoses and have it spray on your inter cooler. No need for a different tune, this will just keep your intake temps lower on boost.
There is some kind of DIY somewhere to do it.
If you need it for a performance application get the STI one, as it will work out cheaper & just as well as the PW (I believe). Its not very often you see second hand Process West ones for sale and @ $1000 new, it not really worth it IMO. I still have to do a test on the GD STI Vs PW TMIC, which I will do soon once work calms down and Mao has some free time. This will hopefully show which one is the king of the TMIC
If its for the bling, bling factor, spend the money on the PW one, as they are very, very pretty
But, have a look,
HERE &
HERE
BOV is easy enough to do. Hope this helps