Installed ALG AKT-EL trigger in the SLR107UR today. Took a little fitting and a little filing, but the install went smoothly. Trigger is unbelievably light now. I'm not sure whether I love it or I'm a little scared. I'll have to put a few rounds through it at some point and find out. Installed a FCG retaining plate while I was at it. I forgot how much of a PITA those shepherd's hooks are...
Installed an Ultimak rail on the SLR107UR as well. It's definitely an imperfect solution, but I'm going to see how it works. The handguard retaining pin on that rifle is TIGHT AF. Unbelievably tight, so it was a little more of a PITA than I thought it would be. Not the Ultimak's fault, but it took a little longer than I expected. I'm going to throw a Primary Arms red dot on there in the meantime and see how long it takes for the heat to fry it. If it dies, it dies. I might try putting the dot on a low rise QD mount to see if I can get a 1/3 cowitness. I don't want an absolute cowitness because the rear sight leaf is going to end up blocking half the FOV in the dot.
I haven't installed my top cover yet... been busy with other stuff today, but it'll happen sometime this week.