"I bought this trigger for my JG BAR-10 after screwing up a modification to another budget 90-degree trigger (Honestly, I HIGHLY recommend buying this trigger as a budget option compared to *other* budget options since it requires very little modification and all you need is a drill and the right bit).
After searching for a different budget VSR trigger, I found this one. It didn't have some of the other random bits that needed modification (Just a trigger, safety, spring guide stopper, and the sear), so I figured it would be much easier to install. I was right!
The trigger box *did* need one modification, but it's simple. The screw holes to mount the Archwick trigger to the receiver weren't quite large enough for the stock trigger screws on my BAR-10, so the holes needed to be drilled larger. I think the Archwick comes with holes for M3 screws, but the BAR-10 uses M4 screws (M#, with the # being the width of the screw's shaft in millimeters).
After drilling the holes, installation was easy. Same as any other trigger.
I do have a warning though, make sure the spring guide stopper is FULLY pressed/locked into place. I had a shop work on my gun since I was scared of screwing up another trigger, but they said the BAR-10 and the trigger I'd bought were incompatible, and they couldn't get the rifle to stop slam-firing. After taking it home and working on it myself, it turned out they didn't push the spring guide stopper in all the way. After fixing the stopper, I got the rifle working no-problem.
I'm currently running an SP150 spring (2.2J with .40g bbs), a 90-degree high pressure piston, and a stock spring guide all in a stock cylinder. If the trigger starts to/does fail, I'll change my review. Until then, it'll still be working!
PS: There's actually one more modification that needs to be done, and it's to the plastic trigger guard. Some of the plastic stops the trigger from pulling all the way back (enough that it's unable to fire), so you'll need to drill and/or cut some of the plastic, that way the trigger is able to pull back far enough to fire.