Boss slod22 denso iridium din gamit ko sa avanza ko, one thing i noticed, quieter yung engine and mas malakas yung hatak, as for fuel economy, noticed ko na di ko na ma attain yung best ko na 19km per 1 liter sa highway, average ko ngayon sa highway is 12km per liter. drop in fuel economy in exchange for quieter and more power engine. next change oil am planning to use standard denso or ngk spark plug to see if my fuel economy will improve. =)