I haven't used this product but I do use VHT to help keep my belt from slipping and I'm still using the stock 3.33 pulley on my S-Trim. Without it my belt slips at about 5500rpms unless I make the belt really tight. If the belt doesn’t slip I usually see 10# at 5800rpms when I shift. If the belt slips I’ve seen it drop to as low as 4#. You can really feel the difference when it slips.