Most seasoned bashers shy away from alloy for anything that sticks out from the core of the truck. Generally, on impact, it either bends and is weakened or, it breaks harder to replace parts on your rig.
If RPM makes arms/towers for your vehicle and bashing is what you intend on doing, then it's the most cost effective durability upgrade over stock plastic. Racers generally stick with stock plastic as it's usually more rigid and that forces the suspension to do closer to 100% of the job it was intended. With RPM, their stuff is more rubbery (not like a noodle), so the crispness in handling can be lost. Bashers like me take durability over handling pretty much any day.
Integy = junk. Pretty to look at, but poorly executed on quality and fitment. Ok for a servo guard or diff case, but not good for anything suspension related or skid plate related. Integy is for shelf queens only (trucks you don't drive, otherwise known as expensive models).
Servo upgrade means faster and stronger. I like the hitec 985MG. A good balance of power/speed/cost, and they are pretty well sealed with o-rings. The only extra sealing I do is put some sensor safe RTV in the input wire boot to take up any gaps between the pigtail.
The savage runs a true big block. There are many to choose from that are solid performers from $150-$200. You can spend more, but if you buy a savage, bashing is where you will be spending your time. So, power, stable tune and compression longevity are the goals to shoot for.
The revo runs a small block style engine (narrower/shorter crankcase). There are quite a few aftermarket engines that are revo specific that will "drop in", but most are near the $200 mark. The stock 3.3 is a solid engine but can be hit or miss with durability.
