Think most of the loss in torque can be clawed back with a good map, but we're talking a few HP either way here, maybe 1% of total power output, so its nothing.
Far more annoying - agreeing with Rich here - is the raspy noise. I dont like it, so would pay the extra for HFCs with less rasp and keeping it road legal. You may "loose" ~1% power with them over decat, but who cares?
As always its horses for courses. Theres no right choice, just the one you feel is the best for you.