#1 sights. Take your pick Dawson, TTI, Warren, Heine, etc.
#2 magwell. I prefer a Dawson ice because of the insert but there are more.
#3 SS guiderod. Again take your pick Zev, Jager, etc.
#4 trigger. I prefer a metal trigger so Zev or Glockstore. Also vanek, glocktriggers, have a smith cut you a nice one?
#5 basepads. I like dawsons just because but you have others. TTI, arredondo, taylor freelance. All are good.
This pretty much gets you a run of the mill limited ready glock.
My favorite addition to this is the SJC frame weight and *thumb rest [generic]*.
Try it and you will ... surprised.