Dan: It's possible they meant the rear end but certainly not in the context of gaining any of the 47 hp as it doesn't gain any hp at all. Could change the et at the track though.
I remember seeing one of the guys changing the rear end gears to 3.69's. On the standard transmission, I am curious if you would gain much in the 1/4 mile, as the 1st gear shift to 2nd would have to be almost emmidiate and you would need an extra shift as it would redline at mid to upper 90 mphs in 4th at 6000 rpm, hence a need for 5th gear and the time to shift. The standard gears red line in 4th at about 110 mph, so higher number gears might get you a little in the bottom end but I think you would loose it with a necessary top end shift.
By the way, I am using the gear ratios listed on HTTP's photo gallery chart as they seem to be pretty close to what my Xfire does.
Anyways, I would still like to see the e-mail Cryil is describing as it would probably answer the questions.