The quality of the greddy kit is :thumbup: Everything fits so perfectly. Mad props to greddy in their designing. They even make the oil return so you dont have to weld. Drag and revhard usually have some fitment problems plus you gotta grind the block a little on most b series kits. I'd go with the greddy but im a bit bias. Tuning is always good if you want your motor to last. The greddy blue box is eh....I'd change it out asap.