Only advice on GPM parts I have is stay away from the aluminum arms (unless you want to make a shelf queen)
I got a set and took them off. After a jump they cracked the hub that attaches the arms to the chassis, and royally bent the pins that hold them on. Honestly it wasn't even that high of a jump(under 2 feet) to cause the amount of damage that was done. I had to cut them off the pins were so bent... Went back to the nylon ones and have had no issues since.

Aluminum parts I use: steering saver set, front knuckles, rear wheel hubs, Front shock tower, and rear shock tower.

I actually recommend the front knuckles seeing on the 2 trucks I own had issues with the knuckles stripping and falling off. Put the aluminum ones on and never had an issue since.