Take the guesswork out of upgrading your 2004 GTO, with the 421-HP Bobcat PerformancePacs from SLP Performance Parts. Each package comprises a group of jointly developed engine, exhaust, and powertrain-management components, all of which work together to significantly improve performance without adversely affecting drivability. Best of all, you'll save $100 over the cost of purchasing the parts individually.

This package includes the following items:

• 85mm Mass-Air-Flow Sensor
• 1 3/4" Coated Long-Tube Headers
• High-Flow Catalytic Converters
• Loud Mouth II Cat-Back Exhaust System
• 25% Underdrive Harmonic Balancer/Pulley
• 1.85-Ratio Rocker Arms (50185)
• DiabloSport II Programmer with SLP Custom Tuning
• 421 Bobcat Fender Badges (pair)

NOTE: Contents may vary slightly from photograph.