[Flyinfool]

The level of bling that will make a difference is very dependant on the heli in question.
For instance, a raptor 50 V2, the only part that needs an upgrade for most 3D is the head block.
For the very most extreme 3D and/or if you are going to run a head speed well in excess of 2000 you may want to add the metal blade grips.
I am at a point where I can tell the difference between metal and plastic blade grips.
Most of the rest is just bling and the extra weight will actually reduce performance.
For someone starting out all that the metal parts are going to do for you is raise the cost of a crash and look cool.

The very best upgrade is still another case of fuel.

I haven't seen a good exploded view labeled with the various common part names. Ill have to do some looking for one. the feathering shaft (also called the spindle depending on brand) is the shaft that goes thru the head an connects the main blade grips.