Hey, i have an 03 750 stock. Ive realized that I need to make some suspension adjustments becasue im getting more into technical riding, not highway blowaways like i was last summer. So, what is the ideal thing for me to do? I realize im going to have to set my sag and preload properly, and adjust with rebound and compression dampening a little, but shout I bother upgrading any parts of my stock suspension? How important is changing the fluid in the front forks? thamks

Replace the rear shock with an Ohlins or Penske. I guarantee you will feel a big difference.
Considiring you have the pretty good Showa forks they should be OK, but a re-valve wouldn't hurt.