I am inherently skeptical about modifying normally aspirated cars.
"custom-modified engine" says to me the modification is internal to the engine, whatever else might be modded exhaust or intake wise. On a NA car like the QP, the major restrictor is the engine itself.
I think a dyno graph before and after are absolutely essential in mods. It needs to show whether there is a gain across the rev range, among other things. Low-rev gains would be far more beneficial to high rev gains for street driving. I will gladly give up 5% at the top end to gain 10% at the bottom. On one of the Porsche forums I frequent, some guy did the whole intake/"brand-name" exhaust/ECU mod package, and actually dyno'ed a loss of hp.
As for seat of pants feel, my Mazda feels extremely fast/powerful on the road due to the way the torque is delivered at low rev when the turbo kicks in, yet in 0-100 the QP is clearly faster by far when I timed them.
Psychologically speaking, a placebo gain is a very real gain and shouldn't be discounted as it does cause an actual release of dopamine in the brain. And philosophically, kids who believe in Santa should be left alone to do so.
Personally, I am like a 7 year old - hugely suspicious and skeptical of the fatman climbing down the chimney, but still holding out some hope if shown proof that he arrived on a floating slate.
And another thing - we don't always drive at 100% throttle right? So.... if we are prodding along at 50% throttle, for a 10% gain, just train ourselves to drive at a constant 55% throttle instead. No?
1989 Mazda MX6 GT 4WS
1997 Porsche Boxster
2006 Lexus RX330
2007 Maserati Quattroporte Sport GT
Last edited by Jinster; 03-01-2013 at 12:22 AM.