Water Meth kit
Rather broad inquiry but methanol is outstanding for cooling the intake charge air in a boosted application. It also increases the octane and the systems are cheap, easy to install and to use.
If you have naturally aspirated they can be effective but the bang for the buck I would think wouldn't be that attractive.
There is tons on info on meth on line good luck
you might check that site out. it had some pretty good info on meth on a nitrous car


