I would bolt the kit on and then drive slowly and carefully to your closest welding shop. Better yet, call a welder and pay him to bring his service truck to you. Bolting the mechanism that holds the front axle to your frame scares me. You would have to check and retorque every 100 miles because that is the first place vibrations and suspension loads meet the frame. I did the SR on my 76 40 and think it made a world of difference, just have someone weld it on for safety's sake, yours and those of us in the approaching lane.
My SR is bolted on. Welding it wouldn't be a bad idea, don't waste your money hiring someone to come weld it. I've been running it very hard for 6+ yrs and never had any of the bolts loosen up. I wouldn't say don't weld it, just that it isn't really necessary. I'm glad I didn't because I mounted mine the original way and now everybody is doing a spring flip, and mounting the front perch so it's offset to the rear instead of leading. I need to do it to improve my angle of approach.