yep mig welds.
i have been told tig is better, neater and stronger.
but i have also been told that mig should be used for exhausts as they are less brittle than tig and as long as they are welded 100% sufficiently then should be fine...
i think i have opened a can of worms here!
Tig is very neat and strong if done properly. My mate works on the rigs welding petroleum pipes his welds are awsome.
When welded properly the weld should actually be stronger than the joining material.