I recommend mig welding it at least. TIG would allow you a little more control where the cracks are, but it’s not necessary. I have welded a number of frames and installed several gusset kits. I usually weld after I sandblast the frame, but if you don’t sandblast it, make sure you remove all the paint from the area you are going to weld. Make sure to overlap your welds on the round tubing to go over any poor penetration from the cold start at the beginning of the weld. And I HIGHLY recommend a gusset kit after you fix the cracks, that will take the stress off of those repaired areas, and it will strengthen the entire frame a lot. I really like the Teixeira Tech gusset kit, but the Lonestar racing kit is pretty good too. The most important part, at least from my experience, is on the gussets that go in the top of the frame where your cracks are, make sure you properly weld the ends of them and overlap your welds. There’s a lot of stress at those points and you want to make sure they have proper penetration so they don’t start cracking.
