(Lower friction pads, like FF ones, will stop the vehicle, but will also require more pedal effort. Some may like the less grabby nature of these pads. However, I don't think these will pass Euro R90 tests. )
Some more generic info from EBC's website. They rated the Yellowstuff R1793 at 1000 deg F. That's way higher than the typical 600 deg F other pads are rated for "hot friction", so it may not be a good direct comparison with, for example, OEM Pagid/Brembo's GG rating.
EBC Yellowstuff R1793 cold mu=0.5=G, 1000degF =0.31=E (!)
(this is not the "upgraded high friction" Yellowstuff with less cold bite and life.) EBC Redstuff nominal mu = 0.5=G (low dust, no steel fiber) EBC Ultimax nominal mu = 0.45=G (low cost Euro-R90 OEM replacement)
The higher the number the stronger the friction (SAE J866a):
E = 0.25-0.35
F = 0.35-0.45
G = 0.45-0.55
H = 0.55-0.65
The Hawk LTS pads I just put on today were marked FF on the back.
The OE Pagid / Brembos I took off were marked GF.
The LTS pads are not what I'd call fully bedded yet, since I can still see some machining marks on the Zimmermann rotors, but already feel about the same as the OE's to me. We'll see how they feel after a little while.
An annoyance: the OE rotors I took off were the most severely lipped I've ever seen (my basis for comparison is Subarus, US cars/trucks and various Korean/Japanese cars). I suppose this can be attributed to the abrasive OE pad compound. The lip, rather than the face of the rotor, actually cut the wear sensor. I think I could've had another 5k miles on these pads if not for that. Oh well, no harm in being conservative and replacing them early (except to my wallet). Here's hoping the LTS / Zimmermann combo lasts a little longer, without the lipping, and the perfrormance is good.