Just in case anyone is interested in doing this mod. I know it's a popular mod and works quite well.
1 - select location, preferably located in the middle of the merge to the exhaust housing and on an angle to make the air entering the wastegate as strealine as possible
2 - die grind the hell out of the standard exhaust manifold until you get rid of the scaley crap on top. Go at least 10mm past where you are going to weld the flange to the manifold
3 - either holesaw or oxy the hole and clean it up with the die grinder, get ready to demolish on carbide tip, they dont like the cast steel. Being a splut pulse exhaust housing, I first drill the hole with the hole saw and since I dont own an oxy, cranked the tig up and blasted the inside of it away. Again, the die grinder came in handy to clean it all up at the end
4 - No just place 3 or 4 tacks around the 'gate flange and weld. did not preheat it at all. Ran 1 root pass and 2 filler passes. One think to keep in mind it is to be slow on the downslope. In my experience, the cast steel doesnt like cooling down quickly, so aim for 1.5-2 downslope.
I used around 90 amps on the root pass, and less on each subsequent pass.
Here is the end result
If anyone has any questions, just let me know