Thanks very much for the feedback!!
I'm curious about the performance issues, can you let me know what kind of hardware + OS you're running on?
New version of the editor is coming soon and should be a lot easier to use as well as documentation.
I'll look into that crash.
I'll likely have some unlockable faster classes but good to know you're reaching the limit of S class, I used to have a faster class but removed it because people said it was too fast, time to bring it back =)