jenvey has been tested but only on a evo engine and produced over 70bhp over the standard inlet which is a vast improvement , but i think anyone could design there own inlet but the key is getting equal amounts of air across all cylinders and this research and development can only be done with flow benches etc and people havent got the resources or money to do this knid of research so they buy the next best thing which is the area six inlet(just my opinion)

cheers paul