The SPE Emperor turbos were designed in-house and are upgraded versions of the popular S300 series. Weak points were addressed including much higher quality castings, bearing material, and machine work and the end result is an even stronger, better design. They are currently available in 3 versions a 63mm, 66mm, 70mm compressor inlet size. All models have an 80/73 turbine. It also has received slight design changes from the normal s300 variant to be optimized for the 6.7L engine to help with back pressure and spool up. Almost all the parts are compatible with the standard s300 turbos including turbine housings and rebuild kits, to help with serviceability and longevity.