Good info MrBios,
Xher, are you over 170 pounds? if so I'd suggest a 2000 contra spring. It's the best spring for larger people. Stage6 has the stiffest followed by Polini. Malossi are very close to the OEM Agility spring, and don't give the full effect
Baring any other issues the Contra spring makes the most difference in hill climbing torque.