I am a big fan of the Ghost Sights on my Glock 34 and 20SF. I have the Ultimate 3.5. The whole kit costs $25 and you can put it in (or take it out) in 10 minutes. No fitting required. I used all the parts in the kit, but you don't have to. Between your stock springs/connector and the ones in the kit, you have a lot of different combinations to try. I really liked the combination of the Ghost connector and striker spring, with the NY1 trigger.
http://www.ghostinc.com/product/GHO_...igger_Kit.html