There were several things wrong with my car that affected full throttle operation and likely made tests such as K&N vs. stock air filter inconclusive.

The in-tank fuel pump was in operative which evidently causes a lean condition on the upper end and mine was. My full throttle switch was also inoperative so the engine computer never got the signal to go to the full throttle fuel/spark map. I wonder how many other cars there also had a bad full throttle switch. Evidently, it's fairly common.

The actual mods are pretty minimal, and not too expensive. Mostly just a lot of hard work.

• Home brew exhaust system from stock manifold flanges on back. It uses the stock manifolds (no headers). It uses 2.5" OD mild steel tubing. No catalytic converters. X crossover just behind the clutch housing. Bullet brand mufflers in the stock muffler location. No rear muffler. I can easily change back to the stock system when DEQ test time rolls around.
• Autothority chip. This was essential because the low end performance was dismal with the exhaust and the stock chip.
• Adjustable fuel pressure regulator. However, the best setting is within the specified fuel pressure for the stock regulator, i.e. 3.8 bar. Set just a little on the low pressure side of normal range. I use a LED bar graph type mixture meter connected to the oxygen sensor to monitor mixture. It's not real accurate but does give some indication of what's happening. I bought it from J.C. Whitney, but the calibration was off so I re-calibrated it for each of the 10 bars to equal 0.1 volts change out of the oxygen sensor.
• 3" flex tubing in place of the stock intake tubes. 
• Flow straightener inside the air box to better direct the air into the mass air flow sensor.
• 7/8" riser under the air filter to give more room under the filter for better, less turbulent, air flow into the mass air flow sensor.

Louie

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