I got W/M in my Golf, and I have not seen an improvement in MPG, but let me tell you that methanol really has some cleaning agent and can give you more power, it keeps all the cylinders clean, it gets most of the soot out the system and also cleans inside the intake manifold, , if there is gunk in your system, i gurantee you that if meth is being sprayed in that area, it would get cleaned up,
These are the 3 main benefits that I like about my W/M system.
gives you more power.
Lower EGT's
clean inside your engine really well