any benefit to swapping heads?

I just had a chance to listen to your video and I have to agree. It sounds great! I agree with above that with stock porting, and stock manifolds you probably won't notice enough gain to be worth the effort.

You say it has "2.25 stock exhaust manifolds". Are you saying you are running 2 1/4" exhaust with stock manifolds? What mufflers are you running? Any drone at any particular RPM? I'm curious because I am running 2 1/4" pipes, and I'm not really sold on the sound of the Magnaflow mufflers I put on, but there's no drone. My car had Flowmasters dumping in front of the rear axle, but there was a HORRIBLE drone about 1200-1500 RPM, so I'm nervous to go back to Flowmaster mufflers.