To take it further you need to start doing quite a bit, new turbo, injectors, rebore, new pistons and rods, cams. The far more expensive and complicated things, not worth it for a 1.4L in a Bravo. There is a fiat 500 build that was quite amazing, he used G-tech and reached 260hp-300hp on a 500 Abarth weighing less than 1000kg.