The Level 1 if for HP levels from 750 - 1500 & features a high stall of 4000rpm's. It is recommended for any turbo the same size or bigger than the SP63. This converter features upgraded lock up clutch plates. They are the largest clutch plates available for this size of converter. Level 2 will also offer a CNC machined turbine hub, sealed Torrington bearings, furnace brazed impeller & turbine, anti-ballooning plate, reinforced turbine vanes, & heat treated Precision hubs. All converters are balanced & pressure tested.