A little more info for those fussy tuners out there.
You can probably run a little more advance and be able to get the most out of H2O inj and Metholated spirits is a fair substitute for Methanol as it still chills the air charge for those on a budget.
Other advantages are that a little H20 tends to keep the carbon build up in the cumbustion chamber to a minimum.
H20 systems show effective benifets on NA performance engines and even more benifets on turbo set ups.
For those with EFI and quality ECU's there is a huge advantage because you have the ability to MAP the H20 injection through a metering solenoid valve. That way you can MAP the injection rate just like a normal fuel injector.
This is something I have been playing around with on my NA rally motor, in theory it should be injecting varying amounts of H20 based on TPI and injector pulse width and load applied. The scope is endless, it all depends on how much time and effort you want to put into it. Same old story - you only get out what you put into it.
Regarding some group N rally cars - Subaru have their intercooler mounted on top of the engine (not ideal) so they run a very simple (read reliable) water injection system that sprays water directly onto the intercooler core, its a compromise but also works well to help cool the charge.