dunno if that was the question,
but megaships do not use the small-ships hyperjump engine, because its to big (lore). they are using whichspacedrive (similar to battlecruiser that jump into combatzones)
That's not actually true. They use the same technology as ALL other ships regardless of size. There is some handwavium about how they are able to jump into CZ's rather than entry stars, but it has been confirmed. I'll try and find the source of that information.
The SFX that they create when entering/exiting CZ's is due to the size of the ship/drive as they punch through Hyperspace creating that effect, not because the use different drives.