Is the hack for nikon d5100 firmware safe?

I'm planning to install the firmware on my nikon d5100 but i'm afraid i might break my camera. Should i do it? Can you give me tips to properly install it?

Since you seem so unsure about what you're doing that you have to ask strangers, you probably don't know enough about installing the firmware to avoid making a big mistake. If you aren't sure about your abilities, don't do it.

It's simply a matter of common sense. It's a $400-ish camera that works perfectly as it is. Absolutely nothing to fix. Why risk it?

Sure. Follow the instructions exactly. Almost all of the people that bricked their Nikons failed to follow the instructions.

Updated firmware from Nikon is safe.

Anything else is dubious.