I spoke to the guy from night7racing.com and he has a s13 1993 with an rb25det on it and he told me the weight did not make that much of a difference. he drives it everyday.. plus with some mods to the internal I hear you can get 700 to 900hp tell me which sr markes that much power... anyways I only want 500 to 650 rear wheel hp. tomei has all the internal part I need to get 700 and up hp for around 3000 dollars.