In my personal Humble opinion - unless you will be doing any racing or the like - a 200S motor will be fine. I really prefer the auto clutch in the tight woods - no clutch work. The S engine is only like 2 HP less if that. Also - with the S engine - you never have to worry about the kick start gears which are kind of problematic with the X engine. You can also get a GOKI electric start kit which makes your Auto-X have a nice advantage. If your primary use will be trails - go for the S engine. If it's performance you are looking for - keep it stock with the X engine.
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