that info isn't all right either. the S13's are high port engines that favor a higher powerband in stock form while the S14/S15's are a low port,and both have the VCT that advances the intake cam 20 degrees in the meat of the powerband to add a little grunt lost to the lowport design,and larger turbo.the S14/S15 turbos are very similiar aside from the S15's divides turbine housing and inconel exhaust wheel. the S15 also has a better ignition,bigger injectors,the 6speed,and a helical LSD.the 6speed isn't really all that weak either.it's been proven to 400hp,the main reason they are swapped in favor of the 5speed is replacement cost.and drifters bust up the 5speeds quite often as well.