Whoops - bumped return. To continue:
Methanol is corrosive to aluminum. When methanol is in full strength, 100%, and when it is in constant contact. It doesn't eat through the stuff like acid, but it will break it down over time. Think about washer fluid, or even our 50/50 Boost Juice - they don't even harm paint, with extended contact. Many years, at 8500 ft, Boost Juice (as washer fluid) used on a Black truck that is parked outside every day. Paint looks perfect.
I have customers that use custom aluminum tanks for their water-meth, and we receommend against it, because over a long period of time, it will break down - scaling, etc. But that is in constant contact, not a super fine mist wisping by something once in a while.
Yes, that EVO user probably had some oil thinning, etc. A big problem with some users is that they use STRAIGHT 100% methanol, not a 50/50 mix or similar. This presents a number of problems. These people think that if some methanol is good, more is better. The first problem that shows up is the fact that methanol, being an alcohol, is extremely forgiving of a rich mixture. That means you can get waaay too much methanol in there and still get a good burn, whereas a gasoline rich mixture would start to miss long before it reached that level of "richness." This means, the car will run great, but there will be more methanol in the combustion chamber than could be hoped to be burned, and there will be some oil dilution and associated problems in the long run.
If there was WATER used in the mix, it not only offers MORE benefit (water absorbs twice as much heat as Methanol and offers huge knock reduction), it helps to control the water/methanol vs. gasoline mixture ratio. If you inject too much WATER-methanol, you will quench the flamefront, similar to being too rich on gasoline. This prevents the stupid over-injection of straight methanol that happens when people decide to use something way outside of what it was designed for.
OK, now consider, as a company, we have tens of thousands of systems in operation right now. We have a number of Class7/8 OTR trucks using our systems. THere is one that has been using it since around 2005. This is an engine that sees around 100k miles/year. It gets torn down and rebuilt on a schedule somewhat like an airplane - so it has been apart many times. The only thing that has been changed, is that it doesn't have the carbon deposits it used to. No increased wear whatsoever. These aren't kids looking for 40hp, these are guys that have a LOT of money in their engines that rely on them to keep food on the table and a roof over their heads. If it caused extra wear or damage, they wouldn't touch it.