I don't believe there should be a loss of torque with the removal of the cat's. 6 cyl motors are torque producers anyhow, removing the muffler would make a difference in torque, removing the cat's should not, lowering the compression ratio will reduce the torque as well.
I did not think about the heat issue though; by moving two of the O2 sensors further down stream it might throw codes.
I used to have a 89 short bed Ford 4x4 with a 300 6cyl, I installed a free flowing cat and the truck personality changed dramaticly. The cab was cooler, not as much heat coming from the cat and I picked up 4 mpg, I changed the size of the whole exhaust system at the same time, larger diameter to make it breath.
Anyone have any idea what the temperatures should be on either side of the two smaller cat's and what the underneath cat temperature should be?