Honestly, any mod I've made to a pistol was a complete waste of money. I assume you're wanting to mod your gun to make it more accurate, right? What goal are you trying to reach? Trigger jobs are about the only thing worth doing in my opinion, only if your trigger is shitty.
(Like a M&P trigger) A fluff and buff never hurts I suppose. But barrels are worthless. Unless you can legitimately out shoot your gun, save your money and spend it on ammo, range time, and some training. Amateurs work on their hardware, pros work on their software.
This is a glock I had, tried a few different drop in "match" barrels and it was a waste of money. The factory barrels are just as good. So no noticeable improvement. This was the storm lake bbl.
Also I know a great gunsmith if you need work done.