teh 6's don't qualify in a muscle car GENIUS. NOw if he wanted something European or Japanese with a 6 that performed and was the latest and greates we would be having a different discussion.... His car will be devalued because he gets a 6 later when he wants to upgrade or trade in as well... No one wants a gutless 4000 pound car.
A muscle car a V8 are synonymous with each other and a certain csound and brute force. That just doesnt apply to a six.
He might as well buy a corvette shell and pedal it around.