I've always run SS springs on my cars with good success. my dart was set up as follows.
SS springs with extra clamps on the front segments. adjustable pinion snubber FOR INSURANCE ONLY. the snubber was set 2 1/2 inches from the floor just to save the u joint if something went wrong and the rear over rotated. I painted a spot above the snubber with white paint so I could check to make sure it was not hitting on launch. it was not hitting and the car was working great. it would repeat 60' times within a few thousandths.
fast forward 150 passes later. I have won the last 2 races with the dart that I have entered, but have gotten very lucky. in both races the car has spun VERY bad during practice rounds, and luckily has gotten exceptable traction during eliminations. I was having to guess the dial in first round because of spinning during practice, and luckily was good enough on the tree to get on the brakes and win.
I have hooked in much hotter track conditions and could not put my finger on where the spin was coming from. then I happen to think to check and see if the snubber was hitting my white paint. not only was it hitting it, but it has dented the contact spot in about 1/4 inch!
that means the springs are bending at launch over 2 1/2 inches! after some internet research I found that the SS springs are made in mexico now and are giving up very early due to weaker metal being used. I have no doubt that is what has happened to mine.
so I ordered a complete Caltrac set up and went to the track with them for the first time today. I set them up just the way the tech guy at Calvert said to, and it went straight as an arrow with the wheels up right off the trailer!
I never had to touch them. the only thing I will say is that my 2step was not working. the MSD digital 2step module has went bad and I didn't get to use the trans brake. I normally leave at 3200 rpm. I just footbraked it to see if the car would go straight and get a base line. I was able to footbrake it to 2900 rpm so I got close to my 3200 trans brake rpm. however the only thing that may make a difference is that my suspension is loaded when I footbrake vs it not going to be when I get the 2 step fixed. not sure it will matter very much, but I think if it does it will be minimum adjustments to make it work.
over all I am happy with the Caltracs and will not go back to the cheap SS springs. if I had the old SS springs that were made in Canada then I'm not sure there would be much difference.