I've got a P229 with barrels in both 357sig and .40. I have the Wolff recoil spring set (17#, 19#, 21#) and was wondering if I was right in thinking that the stock spring is simply a compromise, and it's a good idea to match the spring to the load. From what I understand, the stock spring is 16#. The 357sig works well with the 21#er, so it must batter the hell out of the frame with the stock spring, right? I asked this question elsewhere and was told that Sig knows what they are doing and should use what they supplied. If that's the case, sights, grips, and finishes should never be changed, correct?