to answer the question, wider handlebars will make for a more stable feeling for climbs, but will make your steering feel a bit slower. wider handlebars will also put your hands farther apart, which will open up your chest and let you breathe deeper, which will help you climb farther without getting too winded. the downside to that is that on the descents, more air will hit your chest and slow you down. but if you really crouch down (i'm talkin' teeth to stem here, mister speedy-pants!), that shouldn't be a problem.