I received my BC ER coilovers (12f/10r), installed them and had an alignment last week. I also installed camber arms at the same time to dial in more negative camber as it's mainly a street registered track car.
Have only driven them on the street and a late night mountain run so far, and they are really good. I'm coming from a stock setup, so it's probably not really a fair comparison.
They are 20 from full hard on front and rear atm. They are firm but not bone jarring, and I could easily drive with them like this daily. I also have a fixed back seat which would transfer more shock to me than a stock seat.
Will report back in 2-3 months as I'll have a couple of track days and motorkhanas under my belt with them by then.
Bought them from Garage7. Highly recommend dealing with Evan there as he was extremely helpful and communicative throughout the whole sale as these were custom spring rates he had to request from BC.