Airscape, the numbers that you get from Dynolicious are not reliable. I wouldn't rely on them for anything. In fact, I wouldn't even call them HP numbers.

That said, if you still want to mess with it, it's cheap. Take some test measures before you tune. Then run the same runs with your mods and tune. It should show some improvement. But the numbers aren't really meaningful.

You would actually be better off going to a drag strip, make a couple of runs. Then mod & tune your car. Then go back to the same track and do a couple of runs. Compare your results. You can calculate horsepower from your drag strip times. Those are real numbers, and can be relied on as much as any dyno. Just be careful to account for weather at the drag strip.