What recoil spring is better?

I’m building a full size upper for my p320, just bought this slide from KMT. Debating on running a stock sig recoil spring vs armory craft recoil system. Any reasons I should run one or the other?

Also need to buy slide internals, 3rd party or OEM ok? Or should I get those through sig?

I’m building a full size upper for my p320, just bought this slide from KMT. Debating on running a stock sig recoil spring vs armory craft recoil system. Any reasons I should run one or the other?

Also need to buy slide internals, 3rd party or OEM ok? Or should I get those through sig?