i have a 99 electra glide classic with an injected twin can 88
im thinking of getting a set of 2" true dual drag pipes
the motor is stock as far as i know with only 15k miles
would it be better to run touque cones or short baffles in the pipes for back preasure

 

This isn't exactly what your asking, but this is my experience with drag pipes.

I have a carbed, 80 inch evo, stroked to 89", headwork and a cam.

My electra glide had drag pipes with no baffles on it when I bought it. It was ungodly loud, to the point of being painful after a couple of hours. I tried installing thumb screws in the rear of the pipes and it helped with the popping a little, but no noticable change in torque. I put a set of Peacemaker (adjustable baffles) slip-ons on it and I could control the amount of baffle that was used. I rode it for a couple of years until the y pipe broke for the second time, and put on a set of V&H true dual header pipes with the peacemaker slip-ons.

Wow. What a difference the true duals make. The sound is fuller and louder with both pipes being used and the butt dyno tells me it's faster. I don't notice any loss of torque with with the baffles wide open or any gain with them partially closed. Closing the baffles slightly will make the popping go away.

I would try it without the torque cones first. It shouldn't be difficult to loosen everything up and add them later if you think you need them.
It will be real loud with no baffles at all.

YMMV.