steel is difficult to weld? thats crazy, aluminum is tricky, how is steel so hard to weld? $100 for that weld job is also crazy.
and removing the cat has been proven to have either 0 gains or maybe 1hp and at the cost of more pollution. it is a waste of time to get rid of the cat, especially on a stock motor. once you turbo it and have 400 hp out of it then you may want to run a high flow cat.
unless your cat is clogged (you'd have signs if it was ) then it is not going to benefit you enough to make it worthwhile.
Your best bet is to find an actual welding shop who has experience to weld stuff up. Its one thing to tack it in place yourself, but another to fully weld it so crappy like that, he is clueless on welding.
I agree on NOT doing the header wrap, be a miracle if those welds hold up the way they are, dont add to the issue by wrapping them , trapping moisture on the metal.
I would stop going to that guy for advice!
when you weld metal, you get dis-coloration near the weld because it gets very hot, there is hardly any on those headers, meaning he welded on top of the metal, not burned into the metal.
think of it as using glue to hold 2 pieces of wood together, would you glue the ends or would you put the ends together and glue the outside edge?
in order to get nice welds the metal should have a gap so that the weld can penetrate into the metal completely. looks like he put them tightly together and then welded. And so many spots where he globbed the weld on, obviously does not know how to weld.
the first few times I welded, I used my dads 220 welded and some scrap metal, I had no advice , just wanted to try it, and my welds looked like the ones on your headers.
later on I was taught by a welder who had been doing it for 11 years. and once I was taught the right way to weld, I never looked back, and he was impressed on how fast I caught on.
there is still tons I could learn, I have never done tig or aluminum, nor arc welding. just mig. and structural welding also has a different technique.
but as a beginner myself, ( I call myself a beginner but probably better than most beginners!) I can say that I would be ashamed to hand you the header if it looked like that.
just my .02
1999 4runner 4x4 , Tundra brake rotors and calipers (well worth it!) -wifes