I just sold my other glock today and will be picking up the 20SF soon! It will cost me $520 new. I'm thinking about adding some night sights, and maybe a new recoil rod/20 lb spring. But, I've read conflicting reports of adding anything to a stock glock. A lot of people say they run fine stock even with the hotter Doubletap loads. Also, hardcasts really don't foul the barrel much and a new barrel isn't needed from what I've read..