The Gt series are water cooled >
For example the GT35R (GARRETT)is water cooled. but this is done by tapping into your engine coolant usually.
The water/alchohol injection is mainly for cooling charge air temps.
A garrett turbo and a good sized intercooler will be more than enough .
Unless you are worried about space, were as the AFTERCOOLER, would suit you best since they are usually smaller and can be fittted int otight spaces for that stealth look
My $0.02
Matteo