Older superchargers used a epoxy type coating which was stopped quite some time back like 10 years. Newer supercharges use a teflon coating.
Teflon is methanol compatable.
http://www.catpumps.com/pdfs/Brochures/ChemComp.pdf
Most people who have stripped the coating have at one point used a throttle body cleaner or wet nitrous system. Both are sure ways to peal of the epoxy style coatings, But even teflon is compatible even with xylene.