I've had my eye on the Nowlin kits and think they will fit what I'm trying to do. I just want a good, clean, lightweight trigger for my 1911. I'll probably carry this gun from time to time so it needs to be reliable also. Was thinking about getting a 4lb kit. I'll check out the Nowlin kits and give them a try. I understand these probably will take some fitting to get perfect.
On the two that I've used (Taurus and Springfield), all of the parts were direct drop-in. Not as nice and tight as custom-fitted parts...but that's how they size them so they will be drop-in parts with no major fitting needed. You might need to do a bit of minor fitting on your particular frame. I don't really know that much about the Umarex frames so I can't say for sure.
The slightly smaller dimensions ensure drop-in fit at the expense of being nice tight-tolerance parts. Usually, for a ordinary working gun this is plenty good enough.
If you're thinking about target work though, I would do more customized fitting with oversize (not drop-in or semi-drop-in) parts instead.
A very good recommendation before you start would be to check out a several of the AGI 1911 pistol DVDs...or the whole series if you're really inclined.
-First one is by Bob Dunlap. It covers the basics of the 1911 theory and teardown but not much on in-depth parts fitting.
http://www.americangunsmith.com/app/products/view/1/Colt-191145-Auto-Pistols
-Second, and the top recommend on my list is Troubleshooting 1911 Style Auto Pistols.
http://www.americangunsmith.com/app/products/view/191/Troubleshooting-1911-Style-Auto-Pistols. this one is a very good one to have on the shelf for troubleshooting and problems you've got or might have.
-Volume 3 of their full course is the most applicable to the parts replacement that you're planning though.
http://www.americangunsmith.com/app/products/view/21/The-Ultimate-1911-Video-Course-Volume-1
The Nowlin kits are nice but please note on them that they state 3lbs does not mean you will get 3lbs. Every frame can be slightly different which can alter sear engagement and spring weights
Yup. Each frame will mount the parts just a bit differently.
On my Taurus, I got 3.25lb (just under 3.5lb) with a bit of takeup and overtravel. The actual sear engagment travel is nice and clean.
On my Springfield, the pull weight of the 4lb Commander kit actually came out at 4.75lb with a lot of initial take-up and way too much overtravel. I still want to replace the trigger on this pistol yet so the overtravel isn't a problem on it at the moment.