I have to say the Tsukigi standard for under 200HP applications and the Spec II for built motors. Build quality, quality craftsmanship welds inside and out built to last, great classy looks and very good power without a PCIII and even more with one...I am shipping this pipe all over the world right now. News is spreading like wild fire. Quality.......is the new word and cheap is just that cheap....my 2Cents.