Basically the Stage 3 has a more aggressive timing curve vs the stage 2, and a slightly higher rev limit. Stage 3 users generally notice more low end throttle response.Stage 3 works great on stock motors, even better with after market exhaust/air/ect. Both Stage 2 and Stage 3 operate well within the engine's tolerances. Stage 2 is recommended for bone stock setup with no intentions of adding any aftermarket exhaust or air intake. Stage 3 is recommended for slightly higher performance on a stock setup, and highly recommended for users with aftermarket exhaust/air or have plans for them in future. The item "Yamaha WARRIOR 350 CDI Ignition Performance REV BOX aftermarket AMRRACING STAGE3" is in sale since Wednesday, April 3, 2019. This item is in the category "eBay Motors\Parts & Accessories\ATV, Side-by-Side & UTV Parts & Accessories\Electrical Components". The seller is "gear-junkies" and is located in Las Vegas, Nevada. This item can be shipped worldwide.