I need a need chain so i am thinking about a little bit of a gear change. I see that the 12/40 seems to be pretty favorible. I am also kinda concerned about top end. While i do not see top end alot i still would like to keep it up there somewhat. What do you guys recommend? Does the 12 front make that much of a noticable difference over stock. I am running stock tires. Also, if i were to not like the 12 would i have to completely swap out the chain to go back to a 13, or would i be fine just going with a lower tooth rear and shortining it up. TIA.