FreeGameDev

I finished story mode in 0.10 beta at medium level (231 points). I have unlocked all karts including GNU and Nolok but not Sara the Wizard.

Is it still possible to "cheat" by editing the configuration file in 0.10?

To unlock Sara the Wizard, you have to get more points by completing expert and supertux challenges.

Otherwise, yes the configuration file can still be edited to cheat.

If you want to still try it the “honest” way, I give you a hint: Concentrate on the GPs first. Those give much more points than the other challenges, so these challenges are very important for improving your score. Also try on Expert first because SuperTux is really tough. Proceed to SuperTux when you're ready.
Note that Sara the Wizard requires a lot of points. You'll need to win a few challenges at SuperTux (not all of them!), otherwise your score won't suffice even with 100% Gold/Expert.

About the cheat: See the FAQ <https://supertuxkart.net/FAQ>, but there's an update for 0.10-git:

* "none" = Not won yet
* "easy" = Bronze / Novice
* "normal" = Silver / Intermediate
* "hard" = Gold / Expert
* "best" = Platinum / SuperTux

Then, unlocking Sara the Wizard without cheating can be considered the ultimate challenge.

In 0.9.3, unlocking Sara the Wizard requires 200 points. But when you finish the story mode at easy level, you happen to have 200 points. She can also be accidentally unlocked if she happens to be chosen as the Leader in STK Enterprise (Follow the Leader mode). This doesn't apply to latest version of course.

In 0.9.3, there is no point requirement for any unlock. Your leader thing in STK enterprise is also wrong.

She's unlocked after Candela City.