It would be fun to find out. Engine dyno would work except for the dual exhaust comparison. You could dyno with manifolds then headers for comparison but you wouldn't get the restriction from the single to dual exhaust. All the rest of the changes could come from the engine dyno. A chassis dyno would be better for that and you could note power increases from all the modifications. You would have to calculate drivetrain power losses if you want just engine power specs. You can also spend some time at the track after all the different mods and compare times. Not the very most accurate because of all the differences in traction, temp, baro. pressure and the like. Where a engine dyno is a bit more consistent as far as environment goes) ET and MPH would have to be calculated to horsepower if that's the numbers you are looking for. It's all a guess but the more information you have the closer that guess is. Sorry for the ramble.