Mine's mostly stock. The 4-1 was on it already when I bought it. Non-stock mods were getting the single front rotor drilled, s/s brake line, rear shocks, handlebars, and mirrors. Cosmetic differences were limited to getting the engine cases, valve covers, oil filter cover, and case guards powdercoated. I picked it up a few months ago, still has less than 7K miles on it. Great riding bike, and makes a nice howling noise when you rev it up to redline!