G23f upgrade
 

I'm looking at a "Guarder G19/G23F enhanced metal spring guide and spring" set for about 17 bucks.
http://www.airsoftsupplier.co.uk/pr...ub_cat=Upgrades

What exactly will this do for my gun?

i'm relatively new to airsoft, and i'm looking for some upgrades. Any help is greatly appreciated

what would be some of the best brands to go with if i decide to buy a spring guide and spring set?