I think youd gain power everywhere if you went to something like a PWK 28 which has a flat slide vs the stock round mikuni. Youd most likely also increase your throttle response.
Only thing is, youd have to buy a few jets (or use a 28 mil mikuni flastslide so you can use your existing jets), cause Keihin and Mikunis are different.
Another thing to consider is the PWK 28 mil carbs are OEM on several small engined dirtbikes such as an RM85. And they only cost about 90 bucks brand new from the dealer. Thats a pretty good deal IMO.