Header extensions / torque tubes?

From the engine masters test, collector extensions make huge torque increases, but in the midrange 3000-4000.
It looks like your car never sees less than 5000, (except for maybe the first ten feet) so, not sure they would help.
Still, extensions aren't expensive (I scrounged some diesel exhaust tubing, and made flanges for my four bolt collectors). A couple collector rings and some tubing and a couple welds. I'd sure give em a try.