We use our EDM machine to extrude hone the nozzle to get the 100hp gain. We usually see a drop in EGT's along with a gain in MPG's. We recommend these injectors to anyone needing to replace their current injectors and are looking to gain some performance from their truck. You can run these injectors with a stock turbo system but one of our Phatshaft turbos or our compound turbo setups would be a better match.SE injectors stand for Rebuild and return (You will need to send your injectors to us to rebuild them)NOZZLES ARE SOLD INDIVIDUALLYNO CORE REQUIREDNew Nozzle 2001---2004 Race1 26 LPM 20%