Parts sold by RC car manufacturers and hop-up specialists will always do the job. You pick the one you want by using Keith Bontrager's (MTB pioneer and bike designer) motto...
Strong, light, cheap - pick two.
...which will make every engineer on here smile, and say "how true."
Decide which two you want, and buy accordingly. As long as the part is made by someone who says it will do the job, it will do the job.
Aluminum - light and cheap
Titanium - strong and light
Composite - can be strong and cheap (glass fibre), or strong and light (carbon fibre)
Steel - strong and cheap
See what Keith means?!!!