Tin,
I didn't mean at all that the smaller/shorter header would cost less or be cheaper. I simply meant that the extra HP from the long tubes is worth some extra coin in my book.
Overall I think you are correct with your HP/Torque thing. A good point since most of us are building street cars, lets face it, torque is really what gets the job done on anything but a drag car.
I believe long tube headers can keep the torque by using smaller initial primaries, then stepping to larger tubes at a certain distance. (a buddy of mine has some header building software and says that TTI would have been better using 1 5/8, then stepping up to 1 3/4 based on the specs of the 5.7... He even told me the distance of the step-up, but I cant remember)
I guess I wont really know 'til later today if the TTI's are the wrong/right choice, the motor is going in today, and I hope I don't have fitment issues...
JOE