Got 6 gallons on my gx2 before it became a backup.....as long as amain keeps selling them parts should be easy enough to find....the 3 needle carb has a larger throat than the 2 needle and if I'm not mistaken has a slightly different low end needle for easier (like it was hard in the first place) tuning....I'm sure others will chime in with more info....as long as you run the right pipe combo you can't go wrong.....I recommend the alpha 2090 over the 2072....seemed to stretch out the power band and improve mileage