Thoughts on one vs the other

First, I do not have or have not been in either a scarab or a Heydey. I only have experience with Nautique and Mastercraft. However, looking at the two the Heydey is specifically built for wakesports specifically surfing and would likely be far better than a scarab if surfing is your goal. Scarab took over what was formerly seadoo boats. I'm sure the Scarab is a plenty good boat, but a jet is far from ideal for wake specific watersports. They come with towers, ballast etc... but looks can be deceiving. The Heydey is a V-drive inboard which should be a much better tow boat. From looking at it the Heydey is built only to create a solid wake for surfing and wakeboarding. The scarab is built to be a runabout jetboat. They are two very different animals. Almost like comparing your pontoon to a tournament slalom boat. You probably want to test drive both as the wake will likely be vastly different between the two. A good wake is critical to having a good surf experience.