thats not bad. i'd get it if you really wanted to go a/w route. i still have the big black hose from the previous attempt that you could have or buy off me.
Instead of exchanging the heat from the charge piping with atmospheric air, you use water. so you dont have to mount the intercooler in the flow of the air going by/through your car. it can be more efficient, but the trade off is that its more complicated...there is the need for a pump, water plumbing, and a heat exchanger. another good thing is that your charge piping can be much shorter reducing lag.
This a pic of it... Thats pretty much the reason for doing it. right over the motor, less lag and no heat soak.
On the otherhand. I read somewhere that the old Toyota WRC team used the factory ST205 GT4 A2W incooler for the first 2 years because it was able to support 400hp with a larger heat exchanger and it had great flow numbers. But the FIA banned the use of A2W intercoolers and the went with a front mount.
They are little more pricey, but you will sometimes come across a deal.
ooo I would love to get that GT4 A/W. That thing is sick. That subaru one doesnt look bad either. Its hard to tell from that picture where the inlet is though. Thats definatley an issue on my car since I have limited piping room. I would probably buy it but I'm gonna have to hold off awhile on the HP mods until I get another job.