Y heads, B cam and a Street Heat intake... this car isNOT going to make 300rwhp. The nitrous kit is a wet kit, so throw this out of anyone's line of thinking. The kit is NOT a factor in injector requirements. There is a great chance this car could run fine with 19lb injectors. I suggested 24lb injectors just in case the 19s were pushed a little. I don't see this car getting close to needing anything larger than a 24lb injector.