There you go! Not sure I'd go so far as to say bolt-ins are worthless but welding structural members on a car chassis is definitely the way to go. I made my own subframe connectors for my Duster out of 3/16" wall thickness 2"x3" steel box tubing and 1/4" steel plate, iirc. One afternoon to measure and cut out the tubes and plates to go onto the t-bar crossmember and another afternoon to MIG weld them into place. Half of the welds look like trash but that's only because I didn't properly clean and strip the factory paint and primer on the car and didn't sand the paint along the edges of the tubes well enough where the welds were since I spray-painted them with black chassis paint the day before. I also should have used more C-clamps to clamp the sides of the tubes closer to the framerails. Oh well live and learn, there's still plenty of weld to hold everything together and they've held up fine for the past 4 years or so I've had them in. They did make a noticeable difference in chassis stiffness. Overall I think I put less than $100 into the whole project, plus the roll of MIG wire I gave my friend as payment for using his welder.
I agree with the other comments about MIG welding though, it's quite easy to learn and get the hang of in just a few hours tbh. I took an Intro to Welding class in high school where we tried all different forms and compared to TIG, stick/arc, and especially gas welding (super old-school, not really used anymore) MIG is a cakewalk, just need to get the voltage and wire-feed settings right and use good shielding gas (I like 75% Argon, 25% CO2) which also isn't very hard. Welding is just fun as hell too and super satisfying. Watching the steel melt and glob together is mesmerizing.
