to be honest with you a 600 you will get bored of after a while since you like modding and going fast... 600's are good learner bikes but if you think youll get bored go with a 750 right before the 1000 and a little bigger then the 600... and i dont really know you or how big you are but there are a few factors when wanting to get a bike... imo anyway
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RIP Kevin "Slo_Si" You'll be missed by everyone who knew you my nigga.... I'll see you soon man...