This is the SI0031 parts kit. This insert for your sump has most of the same benefits as the redesigned sump on our 2014 models. This insert will even out your EGT and CHT's from front to rear giving you a more efficient fuel burn and better power and economy. Your results may vary, but it has made a very noticeable improvement on test aircraft. The insert can be used on it's own or with the Marvel fuel nozzle kit. This insert will work with Marvel or AvStar Carburetors. The nozzle kit from Marvel is only approved for Marvel carburetors and there is no data supporting their use in AvStar carburetors.