ive been browsing around and am i alittle lost as to what im looking for for upgraded injectors, the motors a ca18det with a t3/t4 turbo, fmic and im looking for the 250-300 hp range, i know there top feed, not to sure high or low impedance? gtr ones i heard are a direct drop in but there only 444 from my stock 390’s or 370’s?? doesnt seem like much more? rx7 555 also. ? any help would be awesome! thanx