[mann]

I just did a water/meth install on a customer's car and my own afterwards, totally worthwhile and fine for a daily, if the conditions are right.

I prefer the AEM system--totally complete and 3 different jets, progressive controller, 0 leaks, easy to install, common pump easy to replace, filter is 12 bucks for extra insurance, includes EVERYTHING so you don't waste hours piecing things together.

I tune hi compression cast motors with boost, so in my world its a good idea. NOT for more power, but for extra protection. The same rules apply to low compression trying to run over 20-25 psi (depending on CR). But the reality of water/meth is that it IS a complex system to rely on, and really is best as an extra measure of protection. Fuses blow, hoses clog, jets clog, leaks can spring etc...and you might never know it. So tuning for the most power on meth is good only for bragging rights on a dyno, and a recipe for disaster for daily driving or track duty since if it fails the motor grenades.

HOWEVER. If you run a 10.8:1 cast compression motor at 10+ psi like I do, the extra protection is WELL worth it. That is already borderline to pre-ignition territory, and if for some reason it gets too hot out, the intercooler heatsoaks, the fuel trim pulls some fuel or god hates me that day, I still have extra octane and a cooler charge to prevent disaster.

So will it make extra power without tuning--no, and if that's what you want its a bad idea. But it will give lots of extra headroom. As for what to use, any windshield washer fluid that is blue, has no other ingredient other than methanol or water listed is fine.

I was against it for a while...extra cost, complexity, no power...but having an extra measure of protection on an FI car is worth it in my book.