Thanks for the opinions. My final drive is on Fully Synthetic GL5 75W90 Redline gear oil. I never measured before or after compared to mineral oil. Anyway it is not a concern for me on the Final Drive temps, as they work as they are and nothing more I can do to make it more efficient except to change the fluids more frequently to remove metal debris that maybe the cause of early seal failures.
Reduced parasitic drag = better efficiency. That is all I am after. I know it is no issue with the current design, and most live with it's drag which is a cost trade off, IMO of using a floating caliper (lower cost) versus a fixed caliper with double sided pistons (like our fronts). There is hardly any drag on the fronts from what I see on the cold rotors. If brakes were designed to have parasitic drag, then the fronts ought to have some warming to it but it isn't so. If we can have reduced drag without affecting braking performance, why not (and if it is super cheap)
On my quest of such a solution I saw a patent on a single piston caliper with retractable piston mechanism. Many more parts involved and that would surely be more costly and probably a double sided piston solution would end up cheaper.
Questions to be answered.
1) What is the acceptable drag inefficiency as in the stock rear brakes costing the fuel mileage compared to with less drag? Let's experiment with less drag and see what the numbers are. This will tell if it is worth the while.
2) Is the parasitic drag causing quicker wear to the pads? This is the question that I have but won't be answered so soon without using the same Yamaha pads. Can't find them in where I live. International shipping is prohibitive.
None of it is purely scientific because of uncontrolled environments but will evaluate based on the average commuting routes I take.
I have made the spring clips and have installed them. Cost me a quarter. I will post it (on a new topic) if they are feasible solutions after going through some real world tests. So far, it does not affect braking. Worth the while or waste of time......let's just see.
Another reason for my curiosity was on my wife's Prius C. She had her rear drum brakes adjusted and the fuel efficiency dropped by some amount. At first we could not figure out. I lifted the rear on a jack and turn those wheels. Did feel a little drag although doesn't seem much. Went back to the workshop and had them adjusted so that there is no contact. Fuel efficiency returned to normal. After that, I had my old Corolla drums adjusted as well. Now, I am on the S10's case.