First, a warning, this is the kind of thread that could easily wind up with a 100 people in it arguing blindly in favor of their favorite brands. Once you're buying "race-grade" stuff, it's acutally harder to go wrong than it is to find something that works...
Disclaimer over, what I would look at would be....
ESC: I use the
LRP SXX V.2 and am happy with it so far. Smooth and if you can't find a profile from what it comes with that works for you, I would say the problem is the nut behind the wheel and not the ESC. If you want to save a few bucks and you don't need "boost" and you like a linear throttle profile, I'd take a look at the
Novak GTB2 for a more value oriented option.
At this point, I'd be disappointed if nobody jumped in here to say, "Tekin!" However, if you're running any class other than a boosted stock one, I've seen far more people dial themselves out than in with the Tekin. I've seen the preposterous site of someone plugging a laptop into their car to try to re-profile their Tekin when it's obvious to everyone else that a 1/4 turn adjustment on the slipper would be a better way to go.
Motor: Any of the Trinity D3-based motors would be a good bet. The LRP motors tend to run hot but that's all I can comment on for that area.
Servo: I use
This Futaba servo in my SC10.
These are also a popular servo for the truck. Many racers also use the Savox brand to save a few bucks but I don't have enough experience with those to comment. I had a bad experience with a Hitech servo many, many years ago and never went back. I've heard they've improved but you know the old phrase about first impressions. I just hate to see it when someone uses a $40 servo in a $300 truck and then have it never handle right because the servo won't return to center everytime or whatnot.
Radio: I just bought this
Futaba a couple weeks ago and love it. I've always stuck with the "big-name" brands and not the flavor of the week for my transmitter/receiver and that was the cheapest Futaba that had their FASST system and every adjustment you could ever need. YMMV.