I can vouch for the performance improvement aspect of seafoam. I have a 96 Ranger, 4 cylinder 5 speed with 224,000+ miles. It was running like crap, topping out @85 mph. My buddy builds motors told me to try Seafoam. it runs like a sewing machine now, I hit 93 on same straight stretch and got 40 more miles to the tank. I'm sold. BTMO!