A friend told me the world was gonna end last month. She gave me just as much proof as your friend provided you.
The friction codes (and other characteristics) for both are listed in the thread I previously provided. Pick the one you want. It really won't matter all that much either way - practically speaking.
IMHO, DOT4 is DOT4, unless it's "low viscosity" DOT4. For more details though, I follow this from the E39 side of the house.
More information here:
- Brake & clutch fluid
: Brake & clutch hydraulic fluid (1
) & brake bleeding DIYs (1
I once asked what the shims do (the answer is in the thread I already referenced).
It's amazing how dry the Bentley is on brake pads & rotors. See gory details here:
- All BS aside, what are the BMW-recommended brake job "fluids" (1
The bedding procedure is covered, in detail, in the threads I referenced for the OP.
Wow. May I have a handout?
Rotors almost never warp. Especially on street vehicles. If by warping, you mean pad deposition, that happens all the time. It's caused by the way the owner brakes. No sophistication.
- The main causes of vibration
while highway driving (0
) & while highway braking (1
) & why it's never rotor "warp" (1
Price is meaningless most of the time.
The price you pay is not what 'you' think it's worth - it's the sum total of what every other moron out there thinks it's worth.
And those morons outnumber you a million to one (given that most people are styupid).
That's simple supply and demand stuff from Microeconomics 101.
My advice? Same advice I use for everything else.
Buy the cheapest rotors that meet the desired specifications.
Use your brain, instead of your money, to make decisions.
Good luck. Read the references. You'll do just fine.