As others have pointed out(in detail lol) the issue with the top mount isn't just cooling airflow...its actually restrictive at well below 400whp, ie lots of pressure drop, something a good size front mount solves
As for Water Meth injection, i have done extensive testing with it in subaru's and also turbo charged v8's, at the level where it makes a significant difference you'll be using 50/50 water meth at least so the meth acts as an octane boost and you'll be pumping a great deal into the engine....somewhere well in excess of 15% of your total fuel load, thats a big tank for water meth. Also most kits are crude so in effect you'll be pouring the stuff in at the wrong time to get in at the right time ! Unless you shell out for something like a direct port aquamist system which is very pricey !
The yanks seriously need to put the pipe down when quoting gains of WMI, in the real world its more of a skecthy bandaid way of controlling det and when it works it needs serious safety systems to be used all the time. I don't know where you got your info Dan but Methanol is a seriously corrosive thing to your engine...and it dry's more that lubricates.
With the existence of E85 WMI is a mute point, don't even go there.