I've got about 200 miles on my TKX swap. The upper torsion bar cross member was cut without any additional bracing except for the bolt in cross member. So far so good. I do have subframe connectors to help stiffen the whole car. My Torsion bars are stock 318 bars and I'm running a 340 with aluminum heads, fiberglass fenders and hood. 18" wheels. 3:23 gears. I was running down the interstate today at 80mph, turning about 2000 rpms.