it's fully tuned.... but it became worse! The stock is way better I don't understand where it went wrong
This is for you mate, and everyone else that is reading this thread. When you "tune" you vehicles, are you tuning them, or throwing on all the high end parts and hoping that the baseline settings are good enough? When you upgrade your vehicle to the fully tunable parts, you need to tune them. That is what you are paying for. I guarantee if you tuned them especially the suspension, you would have a whole different car!
Here's a good tool I developed to use:
start off with a good baseline for every car.
camber F: in range of -1.0 ---- -1.5 this is relative to the over all weight and its distribution. more weight more camber
camber R: in range of -.5 ---- -1.0 same as front with this
toe F: -.05
toe R: 0.20 for high speed cars, and -.05 for slower cars
Spring weight F: depending on engine orientation FF and FR will stiffen front spring more than rear.
Spring weight R: This is inversely associated with front spring weight, a good weight to start out on spring weight is where the comp sets it.
ARB:4-6
Damper: 5-7 more up front for under stear and more in the rear for over steer
Brake bias F: 5-6 more in front for under steer,
Brake bias R: 5-6 more in rear for over steer
Of course, after you try this will need to tweak according to how the vehicle is now handling.
Implement this and see an improvement!