“After putting 100-150 rounds through it yesterday, I noticed a few things that may need to be addressed right off the bat.”
Put another 850-900 rounds through it before doing anything.
“LWD Extractor is on my list to solve this.”
Before you do that, try a White Sound Defense HRED: http://www.whitesounddefense.com/products/H.R.E.D.-9mm.html. If you have no relief, consider borrowing an old Glock extractor and see if that makes a difference
“The front of the grip feels fine, but by the end of the range session it was starting to tear my fingers up. I looked at something like the Pachmayr glip-on grips to try out possibly, has anyone else experienced this though? It’s not an RTF frame or anything, even.”
Mountain bike innertube over the grip can help. Stippling is better. I radius the edges on all my Glock trigger guards, as they dig into my finger in stock format.
“Is there any way to shorten the travel of the trigger? The weight of it is fine, the only improvement I would want to make is in the length of travel.”
If you want short trigger travel, purchase a high quality 1911 or an M&P w/Apex FSS. Otherwise, learn to work the Glock trigger–it is what it is. I prefer a Glock OEM “-” connector with the stock trigger return spring. Stock Glock triggers are not impediments to accurate or rapid shooting.
[i]Before you do anything major to the pistol, take a good quality handgun class with someone that knows what they are doing:
Officers in our area have reported outstanding training from Pat Mcnamara/TMAC, Magpul Dynamics, Trident Concepts, EAG, PistolTraining.com, VTAC, CSAT, Vickers Tactical, Fulcrum Concepts, ITTS, Kyle Defoor, and TigerSwan––you would be ahead of the game to get training from any of them. Some other folks offering good training include: Ernie Langdon, Pat Goodale/PFT, Louis Awerbuck/Yavpai Shooting Academy, LMS Defense, Jason Falla/Redback One, Mike Pannone/CTT Solutions, Jim Smith/Spartan Tactical, Dave Hall, Don Lazzarini.[/i]