I'm on my second set of ECFs on a Cadillac ATS-V Sedan....275/35R18 front, 295/35R18 rear. My first set had 32 sessions on them, many of which were 25-30min long. I flipped them on the wheels after 3 days for shoulder wear.
They were removed to try a set of 71RS but kept for spares.
ECFs turn on quick and don't get particularly greasy...once hot breakaway is predictable/progressive and they talk a bit although not as loud as a 300tw. They are also decent in the wet, though I've never driven them in active precip - only on a wet/drying track. I've run them at -2.0 and -3.0 front camber, they did fine at -2.0 but I think -2.5 to -3.0 would be just about perfect. I like 35psi hot.
A very very good HPDE tire that will turn to heat-cycled rocks before cording, but they lack pace compared to Super 200s.