Nozzle options stock 30% 80% 100% Core charge must be charged up front 400 bucks , once injectors are returned the core charge will be refunded. 2 yr warranty through manufacturer These are our stage 2 towing/hot street injector. They displace 180cc of fuel and are all a single shot style injector. You will need custom tuning for these to run to their full potential. We recommend running a stock-100% nozzle with these depending on your goals. The smaller nozzle will help with fuel atomization and controlling EGT’s for towing while the larger nozzle will be better for top end power. These may require fuel system upgrades. We always recommend you check your fuel pressure after installation and ensure it never drops below 45 psi under load. ***If sending in 99-03 year model injector cores there will be an additional $150 charge for converting them to single shot style injectors*** These are built from new OE Reman injectors with all new parts throughout the injector then modified to your desired size. These are an exchange program but you can avoid the up front core charge by sending your cores in first.