No, you can actually develop a "feel" while RC drifting. It probably has more to do with transferring what you see to inputs at the trigger and wheel of the transmitter, but it is palpable.

Usually, aluminum parts are for strength, and if you replace a plastic bulkhead with an aluminum one, it's best to do both front and rear. WD is mostly done with weights, either lead or another type. You can see what your balance is, simply, with a tri-ruler. Just set the chassis on the tri-ruler somewhere between the front and rear wheels, and where the tri-ruler ends up, when the balance is even, is where you get the percentage (say, the ruler ends up closer to the front wheels than the rears - estimate what the percentage is, then transpose the numbers). That's a rough-estimating technique, but works.

Drift set-ups are relatively simple, compared to grip chassis. There are some adjustments that are kind of unnecessary for drift, that make a real difference in grip racing. Mostly, the adjustments that work for drift are: ride height, WD, shock spring rate front and rear, caster and camber adjustments. Tires also have an effect, and there is no such thing as an "all-around" drift tire. Some come close, but no drift tire works well on all surfaces. It's why I have multiple sets of wheels and tires of different types, so I can run my drifters pretty much anywhere. If one set of tires doesn't work, I swap them out for another, until I find what works, but if you stick with one surface, one set of tires that work are fine.

Tuning is adjusting the chassis to your style of driving. It takes a while to develop one, but once you have become somewhat proficient, you pretty much know what you like and dislike, so you would adjust those areas of the chassis that would get you where you want the chassis to act the way you want. If you go to the X-Ray site, and download the manual for the T3 or T4, it has all the adjustment possibilities those chassis have, which are pretty much what any upper-level chassis has, and they all act and react to those adjustments, no matter who made the chassis. It's a good reference to have, so you know what each adjustment does, and how it affects the chassis. You will find that many of the listed adjustments are unnecessary for drift, but it's always good to know what they are, if you ever get into grip driving, which is likely, if you stay with RC for any length of time.