Hey Bruce,
I'll start with Eibach 2.25 ID, 7-inch springs for the new Moton Motorsports on my ACR at 800 lbs front, 1100 rear and adjust from there, probably up. That will be with Hoosier R6's to start. This car will be run primarily at the track and trailered, so street ride quality is not critical.
I've tried a bunch of settings on the track too and find the car to be very bouncy during fast transitions with Hoosier R6's. I just can't seem to get the KW's stiff enough to control the springs properly with R6's.
The ACR seems sharper handling and better transitionally with the PS Cups, if you want to run them (that's what they were designed for), but for pure mechancial grip, relatively low price and availability, the Hoosier R6's seem to be a better choice. Also, the Cups seem to loose their grip quicker than the R6's.
I've also run the ACR with Dunlop ALMS race tires and these are the best so far with the KW shocks.
As for seat time, I've got about 6 weekend track events on this car so far and am getting a pretty good feel for the car. It is very forgiving.
Set up is aggressive with 2.5 negative camber front, 1.5 rear. 2mm toe in front, 2mm toe out rear. Caster about 5.7 positive.
On the input side, according to John Archer, one of Tommy Archer's biggest complaints about the ACR during development was the KW shock selection. He didn't care for them either. There is a reason that Viper Comp Coupes come with Moton Motorsport (not Club Sport) shocks.
Bruce, I've got a set of 860 lb / 60 mm (I think) springs that I bought for my ACR that I won't ever use, so if you want to try them on the back of your car they will definitely soften the street ride. I had to order them from Eiback England and will let you have them for my cost if you'd like.
Dan