Originally Posted by MMC Racing

This is my current decision tree:

• Same price, same performance (within 3-5%) - GTM
• Same price, GTM kit out performs - GTM
• Same price, Stillen kit outperforms by 5-10% - tossup
• Same price, Stillen kit outperforms by >10% - Stillen
• GTM kit costs more, Stillen kit outperforms by >5% - Stillen
• GTM kit costs more, Stillen kit similar or underperforms - GTM
• Stillen kit costs more, GTM kit performs similar or within 5% - GTM
• Stillen costs more, GTM kit outperforms - GTM

Comparing performance is not easy, so that will be somewhat subjective. I'll probably compare dyno graphs and boost level. Also, with more boost a pulley change away, I'll work in some value of upgradability into the total cost of ownership over the life of the kit.