whats the one mod you did that completely changed how your bike rides

Ive done a lot of bolt ons over the years but honestly the single biggest difference I ever felt was going from stock suspension to properly set up springs for my weight. felt like a completely different bike overnight. everything else — pipes, jetting, bars — was nice but nothing came close to that moment when the suspension actually worked with me instead of against me.

curious what did it for you guys. what was the one thing where you were like damn why didnt I do this sooner