honestly i dont know. ive seen plenty of stock head/cam SRs (i think the majority of them were non VTC if that makes a difference) do above 350 on bigger turbos...but anyone can crank out power on higher boost, im just used to seeing such good tuned setups. i guess technically you could make up to 40-50hp gains from intake manifold and cams, but i dunno. they must make a world of difference on SRs. im used to just seeing stock head/cam KAs do 400-500 with just forged bottom ends, on not-that-high psi levels.