ll you will get here is a 'seat of the pants' dyno test. I do know that one or two of the posters here run short TORS with the cat and complain about fuel mileage. That coupled with their tune will account for that.
I assume i'm one of those, but check this out. When i recently decided to put the seat duct back on my mileage has been up back to almost where it was as a 1600. I got 42 last time i checked ! Thats actually as good as i got as a 1600, but i think that was due to the riding situation that day. but i have been hitting 40 for the last couple or 3 tanks. And i'm running a custom tune, so theres a chance if i went back to the stock 1700/tors tune i'd do even better. It's not the tors either, as i have been using those for a long time and i never saw any mileage difference between those, the long tors, or the stocks all with thier corresponding tunes. The mileage variations i have been getting i now know are almost all if not all due to the seat duct being off.