Crosman P1322 Modifications

So I've got the Crosman 1322 Air Pistol. Looking to do some upgrades to it so it'll shoot better. I plan on getting the backpacker pump, the steel breech kit, and even the better trigger, but I'm curious what else I can do to make this a better firing gun. I'm seeing stronger hammer springs, 14" barrels, and other things but I don't know much about those. I can install them if I have them, but I don't know what they all do. So please give any and all advice you may have and please link me to the items you talk of so its' easier to find. Thank you.