You'll find by reading anything on this forum that a lot of info in forums is BS anyway. I remember when back in the day I thought the 3000 pipe on my mkIII supra was the turbo itself cause I had no idea what a turbo even looked like.

An aftermarket downpipe intended for your make and model of car won't require an external wastegate so don't worry about it. The best way to figure things out is to start taking shit apart then call somebody to help you put it back together when you can't figure out how it goes back together It worked for me. Have fun with the car and feel free to email me if you have any more questions.