compatible parts to swap with my bike?

Hey guys...
Anybody know where I can find a source for compatible parts that I can swap and interchange with my bike. I really hate the way my fork feels. I put in new prgressive springs..heavier fork oil...have dialed up..dialed down....tightened preload on spring and lessened...but nothing works. When I hit a bump or crack...it hits hard and feels like shit. I feel the hit right into my handle bars. Fork seals feel good..no leaks. I wanna try and put another set of tubes on my bike. Trying to find another bikes forks I can put on mine. I've ridden other bikes and they just glide up and down over the bumps..etc..