I'm not familiar with the srt6 intercooler, but it is a water to air system, so I don't think its possible to use this. I think your better off making a methanol water injection system that sprays directly into the manifold. The great thing about using alcohol is that it has a cooling effect on the air charge, this is much cheaper way to go than purchasing anything from Renntech and probably more efficient.

This will give you some ideas on a home brew kit, most of this stuff can be ordered from McMasterCarr http://alcoholkits.tripod.com/ this is mostly for GN's.

The price is right, $300 will have you making another 20-40 hp, that's something renntech cant do, lol go for it!