I had one from Classicswede in the UK and after taking 3 months to arrive it did not fit. The rolled edge on the turbo outlet end was wrong and needed lots of grinding to reduce its size to fit inside the 3 studs, also the other end had a strange bend in it that pointed the pipe up into the floor right at the end, so that was also cut off. In the end I did not use it, lost all confidence in it.
When the B23 + T was getting back together there was a change of turbo so change of exhaust outlet, then there was lock down and everything closed, so I just made one. Was the first real welding in 20 years and first time ever with a TIG - it came up Ok. Bought the pipe from performanceexhaust.com.au and a 90 deg bend, also a 60 I think. The flex joint is on all new cars so I figure it has a purpose so added one of them. Little bracket to mount to the back of the block there too. Mark form Berry's helped me out with a trashed old downpipe that was a donor for the mount onto the back of the turbo (thanks again Honey). I later found them online for $80 out of hte USA. Works a treat, though time again it would be a little different - as is always the case with fabricating these things. It is 3 inch mild steel save for the flex which is stainless. Time again I would go all stainless and keep it closer to the block as it is a little low when on the street. After the pipe it goes to 2.5 inch pipe then at the diff goes into the OEM replica 240 turbo exhaust (from iPd).
Another option is the modified 740 turbo downpipe. Been done literally thousands of times. The internet has many records of these efforts. I had one of these in the B230FT 240 wagon and it was fine. The exhaust shop shortened the top of the pipe just near the turbo 30mm, then a joiner pipe to the iPd OEM copy turbo exhaust kit. That worked a treat. I have a 740 downpipe for sale here if you are interested, should be in the for sale section somewhere.