I have a Glock 3rd generation Model 20. I have ordered a KKM 6 incher for it. I am shooting some Masters ammo 180 FMJ which is I believe to top end (Velocity wise) of 10MM. I want to order a Wolf heavy recoil spring. Should I get the 20lb spring? Is there anything else I need to get with it? Will the spring work with the OEM recoil rod that is in the gun right now? Thanks guys for your help.