Want more power

I love my little gk but man it's slow. I have a ktuner v1.2 and heliums and neo gen 205/50/15s. Didn't notice a single difference 0 to 60. I've even played a little bit with some of the settings in the ecu. Any advice else wise? Was hoping to not mod the hell out of the thing. Unfortunately I'm on the edge of trading it off for something quicker. Other than wheels and tuner it's basically stock.