Dont use a stock single core s13 radiator, barely adequate for an s13- same size as n13 pulsar core lol. I replaced pulsar one with s13 and used same mounting holes etc. The core is same thickness in tubes and all. Speaking with rad guy now as I'm getting something better, r32 gtst is twin core but need to check as 15-20mm taller in core, but I'm Also looking at a Honda one as it's Also twin core- same width as s13 between rails.