big block abody manifolds

why? the fenderwells are simple to install, they give great hp, clear everything,they are virtually within6 inches of the body, give great clearance, especially with the 400 strokers,allow easy plug changes,simple exaust system required,they give the car a great look,etc,etc what are the advantages of under chassis? price? I think the hooker super comp fenderwells give more hp than the schumacher, im hooked on hooker charlieps they just look flat out great on an A body charlie