I heard that you should do abs slow while releasing one breath per rep.... I also heard you should so them fast to get them to burn... Also was wondering what is the better for your abs, i know cardio and diet, but i wanted to know if weighted abs were better than regular ab workouts???
When doing abs, you should be CONTRACTING YOUR ABS to do the exercise and not just DOING the exercise movement. Doing it this way is more determined by the contraction. If you're doing things too fast, then you're not really contracting, but doing the movement with not a lot of thought.
DIET is the best thing you can do for UNVEILING your abs.
Resistance exercise is the best thing you can do for BUILDING your abs. Any exercise that stresses the core is goign to help build it up (i.e. squats, deadlifts, powercleans, cleana nd press, etc.)
Cardio is NOT that important for either seeing ab defintion or building muscle there.
Re exercises for abs, it depends on WHAT you want your end result to be (although this will also be determined some by genetics). If you want deeper grooves between your rectus abdominus, then weighted exercises (i.e. weighted cruch, etc.) are the way to go. If you don't want such deep defintion, then unweighted exercises would be better. However, a combination of BOTH types of training will be fine.
As for how often you do abs a week: TWICE is enough, for ~100 reps in TOTAL per time.