100% what the others have said. I have several sizes - one up to 200NM, one to 100, another to 50. I even have one that does inch-lbs for use on my mountain bike.
I saw something cool the other day, it attaches to any wrench and instantly makes it a torque wrench:
Won't fit in many spots, but might be a decent option for the really high torque parts like the countersprocket nut. From what I've read, even the cheap ones like these are typically extremely accurate.
Whilst i have various torque wrenches I only use the one for the lower end when working on engines. Anything that needs big numbers I go by feel. So if you're buying one buy the one that does the finer stuff.