Same thing happen to me, recently I changed my IC piping from 2" to 2.5", now I see that my car has definitly less smoke, less egt's (big advantage) in the other hand I lost a little bit of the quickness from the get go I could feel it I know my car,,I really like quick sprints they are fun. but now I believe that if I continue to open the air flow with long duration cam and porting the head, my air swirl will suffer even more, making my car more letargic from a quick roll, peaking at a higher RPM,(no fun for me),
I am not an expert on this matter and please correct me if I am wrong, but I think If you would like to open the air passage in your car big time, I think the 17/22 is not the appropriate turbo to do that, you would need a bigger turbo with bigger blades to push all that air through the bigger tunnel.
I will have my car Dyno probably next month, so we'll see what kind of numbers I get after going from 2.0" to a bigger 2.5" IC piping , I will compare it with my old dyno, IBW I am also afriad about taking my car to the dyno, I would not like to pick up one of the rods flying across the shop.