I am guessing that you are a fairly new brewer, so this is my advice. Take it or not.
Brew the kit as it is. There is a balance in a good recipe. Once you change that then you have to change other parts. If you add more fermentables then you have to add more hops to balance it out. Until you really understand recipes, you are better off following the recipe as written.
You are better off learning how to control all of the parts of the brewing process before you start changing things too much. Learn about things like proper yeast pitching, making proper sized starters, controling fermentation temps etc. Make a few good beers before you go crazy. I know that as a new brewer you want to try new stuff but believe me, getting the process down will have you making good beers faster than trying stuff that you do not know will work.
It is a lot like cooking. You can just open up the spice cabinet and start throwing spices in, or you can learn which ones work together. Too much of one throws a recipe out of whack. Learn what works and then improvise from there.