So I went to the track last night for the first time with my borla true dual exhaust.
On Feb 27th @ 11:30pm the track conditions were:
52(Temp), ~20 Humid. At the time I had the Z tube + Stillen air box, and the resonator was replaced with a 22" magnaflow one.
My Time from Feb -
R/T-1.450
60' - 2.291
330 - 6.264
1/8 - 9.525
MPH - 75.27
1000 - 12.336
1/4 - 14.697
MPH - 95.74

Last Night weather from weather.com
79°, 73° dew point, 91% Humid, 30.13 Press. (in.), From SE, Time of run 7:30PM
9mph (wind). Car had the same mods except exhaust was replaced with the Borla True Dual System.

R/T - .642
60' - 2.321
330 - 6.316
1/8 - 9.544
MPH - 76.34
1000 - 12.309
1/4 - 14.619
MPH - 97.68

Considering the vast difference in temperature and humidity + having a slower 60', what do you think of my run with the borla.

(Note my highest MPH of the night was a 97.96, Car is an Automatic 03.5 Sedan with Prem,Sport, and Aero)

 

It looks like your car really came 'on' in the back half of the track. Virtually identical at the 1/8 mile mark with 2mph higher trap speed tells me you are making a lot more hp and a wee bit more torque. (taking into account the less-than-ideal air)
Atmospheric was reasonably good the 1st time, so your similar low-end numbers indicate a small improvement down low.
Big improvement in the mph says hp increase. Same air should put you into 14.55 range IMHO.
Humble guess would be ~15hp improvement.

'04 G35X Graphite/graphite, NAV, wood, premium

 

I forgot to say NICE TIMES!!


'04 G35X Graphite/graphite, NAV, wood, premium

 

You didn't mention your altitude or barometric pressure but I'll assume sea level and 30.13 for your first run too.

On the 27th you were making 106.3% relative HP to rated.

Last night you were making 100.1% HP.

However, according to the aviation formulas I'm using, the relative humidty at 73 dewpoint yields a 81.9% relative humidity, so I'm not sure what's up with that. Also, either you left out the wind direction or you thought pressure came from a heading, but in any case if you know HP to 1/4 mile times conversions you can cipher it exactly.

I'd say the Borla did the trick as you scored .08 of a second better missing 6.2% HP due to temps if I'm reading this right! Nice.

2004.5 Coupe/5AT/Ivory/Everything but chin spoiler/Z Tube-Popcharger/Crawford V5 Plenum on the way

 

And they call boxing "The Sweet Science" ? - Not to a gearhead ! Thanks for the info on how the weather conditions are such a factor, Catatafish. That's why this forum works, especially for us "noobs".

Sport Sedan Fan
2004 6MT Sedan/Sport/Navigation/Premium/Aero

 

Thanks . Now if we could just get all these vendors to log their weather conditions when they did their so called dyno tests we could know what to buy up front!

2004.5 Coupe/5AT/Ivory/Everything but chin spoiler/Z Tube-Popcharger/Crawford V5 Plenum on the way