There are a few dynos out there that show an overlay of stock vs SPD turbo adapter loosing 50-150tq from idle to 2700rpm and 40-70hp loss from off idle to 2700rpm. This was a big debate on facebook about these adapters a few weeks ago. Im not sold on them after seeing the before and after dynos in the same day. for your average daily driving and towing they dont make sense for me. 20hp improvement at WOT3500-5000rpms vs a a 150tq loss at 1800-2700 rpms for daily driving are not worth it to me.
This post tell me you don't have a deep understanding of how turbochargers work.