Yes it goes all way down, I decided to split it, because there was rust free area down there. This job , my oppinnion, fairly easy. Just take your time and what needs to go where before you weld. I used sheet metal screws to attach both parts before welding.
When I was ready, I removed screws and weld those screw holes up.
I braced it from winshield frame and I also welded two strong pipes from chassis beam to ground, just below firewall. With that setup I could not see any flex on body.
