yeah i thought the series one only came with aluminum upper intake but looks like i was wrong...and the series one intake has a different design than the series 2. Yeah there isnt much difference in power but im looking for the OBD2 version mainly. the series one was OBD1 and im not sure (may be easier) how to wire in the series one engine. But i wanted the obd2 because im able to read more info off it with my laptop and scanners and i know more about the series 2 and 3.