I've heard of them. Two guys here run them...one a Super Duty on 12" Atlas Springs, the other 14" springs on a 78 Suburban. Both are happy with them .
The guy with the Super Duty was gonna go National, but they wanted $3300 for a set of four springs and a 3 month wait. Atlas charged him $1300 for the set of four and got them in a couple weeks/forums/images/graemlins/cool.gif
Oh yeah, and there is one other guy I talked to who runs them and said he is very pleased with them! Hope that helps.
My buddy is supposed to call me with their phone number and I'll post it when I get it...
I've also heard great things about Alcan Spring in Colorado (1-888-321-0870) and Deaver Spring is supposed to be good to (1-714-542-3703)
Anyone else here anything good or bad about any of these companies??