denatured alk works 100***37; fine and is no worse for your car/system than methanol is.
You dont get the same effect that you would on meth, however the difference is pretty small and denatured will still yeild huge gains.
I ran 50/50 distilled water/denatured alk in my alk cars (and will be doing the same again in this one once I hook it up) and it was awesome. 4+ degrees of timing, 12.5-1 a/f and 23lbs of boost on the stock STI turbo.
no knock, ever.