Cane sugar won't add any flavor (most sugars won't), but at the same time it won't do any harm. Personally, I'd follow the directions and use the amount of sugar called for. That's how you;ll get the correct body and gravity for the beer. For priming, don't use extract....it's not 100% fermentable. Table sugar works great for priming. I use about 1 oz. of sugar for every gal. of beer.