water/methanol injection PROs N CONs?

[deedee]

a friend of mine is going to give me hes water/metahnol injection system and im planning on using it on my expy.im just wondering if its worth it doing/adding that to my engine and what are the pros n cons of having one.
im also wondering if ill need a tune again to get the most out of the system since im already running rich to begin with.
the expy has a procharger,chip,exhaust,intake and a custom tune to accomodate the SC and the 100 shot of NOS so like what i said...its already running rich cause of the SC/NOS combo.if i dont do another tune and works just fine..i might ditch the NOS altogether.the system will only inject a fine mist when in boost and/or *WOT so as to not damage the engine altogether by spraying constantly.it should help clean all the carbon build up inside the engine too.
it also helps doing more aggresive timing(not sure if the 5.4 triton will benefit tho) with out detonation and be able to run higher boost.
the only CON ive seen is since methanol burns alot cooler than gas..it might screw up the pistons but if the water/meth mix is just right and the spray isnt too much..i think itll just help for a more dense air coming in and a better burning and pressure inside the engine producing more HP in return.
what kind of HP gains am i looking at too?ive seen/read people getting from 30HP all the way up to 100HP(with tune) and almost every forum ived read..people are pretty much 50/50 on its PROs N CONs.
thnxz guys..

[lytspid]

pros..cooler intake charge and higher horsepower ratings...cons is - yuoll have to find a good supply of methanol here, BTW..we are distributing water/meth system here in the philippines..

[deedee]

its only 1 dollar/gal of meth here where i live and its easy to get them here.alot of people also told me to just usewindshiled washer with deicer since deicer has more meth mixture or use engine coolant rated for winter use.they both have high methanol count too.
thnxz for the advice tho.