What can i do as far as customization?

Question

its a rws 34 panther

Answer 1

Answer: As much as you are willing to attempt.

I would start of with the stock.  You can change the shape to make it more ergonomic with auto body bondo, sand it to the shape you want, and repaint it.

Next, you could install a scope mount and mount a scope.

More involved changes might include removing the front sight, threading the muzzle and adding a cocking handle.

To get more velocity, you could take out the coil spring and replace it with an air column spring.

These are just a few ideas.  You are only limited by your imagination and your bank account.