Up for sale is a gently used 9c manufactured in 2013. It has the following modifications/additions:
Apex Tactical Forward Set Sear kit with aluminum trigger (All orignal components also included should you want to revert to stock configuration.)
Factory night sights*
LF Arms standard length...
Unless there is something wrong with the existing finish on your barrel I would suggest against it. While it won't chip or flake, with proper application, cerakote applied to a barrel is going to experience excessive wear from firing and cycling. Like the rings on this Shield's barrel.
As...
From a quick search of their site there is no such part number as 100-073. Looking at the list of parts for the Shield there is a 100-063 which is a sear for the Shield 45. Could that be what you ordered?
The rear CORE sight dovetail is a good bit smaller than the standard M&P rear sight dovetail so they're not compatible/interchangeable. Something like this would work for your factory dovetails though.
In the shop where I work we use Slip2000's 725 cleaner for most gun cleaning we do and then their Gun Lube when we put everything back together.
The cleaner's nice because it's water based/non-toxic/etc. but still incredibly strong and the oil doesn't seem to break down/dry out/gum...
It works for the Glocks because they use a common frame between the 40, 357 Sig, and 9mm calibers. (And the fact that the diameter of their brass is close enough to still utilize the extractor for the larger rounds on the smaller rounds.)
As the 9mm and 40 Shields use a different frame than the...
Putting a non-ported barrel into a ported slide won't cause any detrimental effects, you'll just have decorative rather than functional holes in your slide.
Putting a ported barrel into a non-ported slide on the other hand...
If you're careful and only turn the tool/bolt about half to a full turn you can generally reuse the original liner.
Also, Speed Shooter does have the Striker Channel Liner for non-45s.
That pre-travel you got rid of had to go somewhere. The geometry of the new trigger is such that its default position will be further back.
As for the pull weight: did you get an action enhancement kit or a forward set sear kit?
If it's the forward set sear kit you can make your pull heavier...
Minimum amount of parts you'll need to do this:
Sear Housing Block
Manual Safety Lever
Manual Safety Lever Detent Ball and Spring
You'll then have to dismantle your existing sear block and put all those guts in the new one, add in the safety spring and detent so that it looks like the...
The closest I've gotten is using the factory sear spring, factory safety plunger spring, and heavier of the 2 kit trigger springs. I want to say it was a 4.5-5# pull but it was on a customer's gun and I've slept since then.