The plenum cover and elbow are only available from companies such as collins as a complete kit and not seperate.I have a plenum but cannot get hold of an elbow anywhere,im going to get one made now.Jenvey do a replacement direct fit to rs500 elbow, throttle body,but it looks different to the original.There is also a bloke on ebay who has remoulded some from an original but hasnt got the throttle butterflys made yet,but have tried to contact him to buy one but has not replied.