I took plain monohydrate pills last season with good results. I'm one of those weirdos who likes enduro events as much as sprint events. I don't lift super heavy or go to a gym, mostly plyometric/lunge/squat type exercises with free weights once a week during racing season, and maybe 2-3 times a week off-season. I definitely noticed a strength improvement on < 1 min efforts. I could spin a bigger gear, chug along with a lower heart rate, and have enough matches to light up for sprints.
As far as hydration/nutrition, unless you're a pure sprinter or bodybuilder, you'll be doing enough cardio just riding and racing and won't notice any major bloating. So you also won't have to drink much more water than you normally do (unless you're peeing every hour, then you could probably dial back the water intake). Grazing vs 2-3 big meals helps too.
Like most here are saying, stay away from the blends that have caffeine and other stimulants. Not just because of the fda/wada stuff, but because they are prone to causing headaches, especially if you already drink coffee and other caffeinated drinks.