A quick Google search for "cubase 55 3 best download" will return dozens of torrent sites, file uploaders, and Russian forums offering cracked versions. Here is why you should avoid them at all costs:

: It is one of the last versions capable of importing very old .all and .arr files from the Atari/VST 5 era, which can then be saved as .cpr files for modern Cubase Pro versions.

Improved reliability for running older 32-bit plugins in a 64-bit environment.

Do not risk your music, your computer, or your legal standing for a phantom version number. The best download is always the one from the source.