you can plug weld. I looked into getting a spot welder, not really worth it if you're not going to be doing alot (might be worth fitting the gaurds preping them and taking the car somewhere to get someone to just do the spot welds?), i took both rear quarters off of my ute and just plug welded them all back on, ground em off with the 100mm grinder when i was done. came up a treat. if the grinds dont come up perfect you can always slap a very light coat of bog along to get that ultra smoothness i guess....