Bad Dog subrframe rails

[thoseRZZZs]

Hey everyone, I'm getting a semi-serious cage and front strut-tower-to-firewall brace made for my Z this winter. I also got Bad Dog front subframe sway-bar plates and jack plates. My question is, are their two-piece subframe kits meant to be welded "over" top of of the factory rails and connect in the middle under the car? Or do you cut the factory subframe rails and weld these in place? I know it sounds stupid but I dont know and can't decide if I should get those, order the expensive ones from Datsunstore.com or what. Any advice is greatly appreciated. Thanks!

[240260280z]

All the BD rails I have seen are weld over's. The owner, John Jeffrey, is a racer so they are designed for function first.