i had a set of ruf's years ago that i had matched up between two stock sets.  i welded a bolt into the whole on the spring where the stock clamp was located.  drove the truck like that for over a year, and it was out at the beach everyday in the dunes.  just short of year, the spring that i had it welded to cracked and broke right where I had welded it.  spring steel will hold the weld, until the spring actually flexes.  then it will break.  not a good idea to weld in my opinion.  I have some gorilla tape holding my rufs together now  .  my  if it's worth anything.