I agree with you. They are super loud. I bought an existing tank that had a Via Aqua in the Sump. When it burnt out, I bought another one. The new one is much louder than the old model.
Right now, I have mine sitting on a gladware container that has the lid on and is about 1/2 full of sand the rest water. It cut the noise way down.
Your modification link looks interesting. Before I'd try it, I'd want to have a back up pump. I'd hate to mess with the main pump on my tank without a backup.
Best of luck,
Roy