Adding more starter to a bread recipe

Hi everyone - I'm new to this forum and am impressed and inspired by all the knowledge here.  This is my first post so hopefully I don't mess it up. :)

I've made Tartine bread before and was wondering what would happen if I added a LOT more starter to the dough?  Of course I would sub-out the equivalent in liquid and flour from the final recipe to keep the final numbers the same, but what difference would it make to the process and the final product?  Would it be like adding more instant yeast to a recipe where you'd get a faster rise?  Would you get larger bubbles and more of them in the baked bread because of all the extra wild yeast and bacteria?  I'm toying with this idea but don't want to sabotage a 2-day process of bread making if it's a surefire fail.  Thanks!