I would think RPM. I am not too fermiliar with that model so don't hold me to my words. however, I would think aluminum would get bent and stay bent. Maybe get an lst owner to let you know more.
definetly RPM. aluminums can bend which is just as bad having them snap off. RPM is very strong and i have had no problem with them on my revo for the past 3 months not running it pretty hard about 2-3 times a week
Nitrogator has you covered. Rpm with lunsford. Tough combo to beat. It's what I've ran on my aftershock for most of last season. As my buddies were snapping their LST2 arms and axle carriers... I just kept on bashing.
RPM is the way to go. Alum will bend in cases and you have to try and straighten it back out or pay for a new set. RPM is very strong and has flex if you need it, along with a lifetime warranty, so if you ever break them you get new one's for FREE!
I used the Dynamite Aluminum ones. I never EVER bent or broke. I recommend either ones. I have RPM ones going on the LST2 Build up I have now. If I had the coin, I would go the other way since my previous experience. Either ones mated to Lunsford TB would be great.