I suspect that I have considered / Installed most of the Mods out there, and there are some great ones. I have the LC9s Pro, but other than Fiber Optic / Tritium sights, the other mods are the same. Laser Sights: Crimson Trace:
Kind of out dated at this point, as the grip activation button is a pain. LaserMax:
The older model is now cheap, and the new combo with light and grip sense seems good, if the largest of the group. ArmaLaser:
I ended up with this one, it's grip activated, and the battery lasts FOREVER.
The various stick on grip stickers, such as Talon, are nice, but don't add much in the way of improved grip, and tend to peel off over time. My suggestion is a grip sleeve. Grip Sleeves: Hogue Handall Beavertail:
Looks great, stays in place, takes some work to install, if the grip works for you, probably the best. Pachmyr:
Looks cool, easy to install, can shift a little, I find the grip better for my hand size.
Magazine Grip Extensions:
If the stock finger extension is not quite enough. Garrison Grip
1" Extensions: Look great, and gives even big hands a full grip.
On the subject of magazines, the MagGuts
+1 conversion kit is great, and has worked flawlessly in all 3 of my 7rnd (now 8rnd) magazines. Replacement Trigger:
Galloway makes the Aegis Short Stroke Trigger
: It is a flat trigger that is said to reduce a significant amount of pre-travel. I might have considered it, though it seems excessive, and looks... odd.
Fortunately, there are some really great alternatives... Powder River Precision
makes a Trigger Kit that replaces the sear and trigger pivot, and reduces both pre-travel, over travel, and pull weight. I love it! M*CARBO
makes a replacement trigger return spring that takes away additional weight from the trigger pull (cause yeah, that's definately needed). That said... I installed it.
There used to be a replacement recoil spring from Galloway, but they dropped it, as the new springs from Ruger are great.
There is also a weird slide spider sticker that goes over your slide serrations but... why? Maybe if someone needs that extra firm grip for racking the slide I guess. SAS Tactical
had been doing some custom slide work, and still does custom barrel work, but I suspect that is not what you were looking for.
That covers most of the stuff out there, other that coatings and such, but if I missed something, I'm actually surprised. For reference, here is my Pro.