they claim that it needs to be cleaned at around 50,000 miles...
It's been only 10,000 miles since I installed the racing beat's intake system (REVi)
Is it safe to replace the filter now?
or it really does not affect my car's performance until it reaches to 50,000 miles?

Thanks

 

You don't replace it, you take it out and clean it. I did it once a year during a winter weekend day ( in the garage).

 

listen to expo, Just buy K&N's Filter cleaner kit and clean it.

 

^+1
Autozone sells the K&N Recharge Kit.
I just cleaned mine this past winter.

 

It's a forever filter, that's why it's expensive. Just clean it and put it back. I have a drop-in k & n filter and all i do is clean it if it gets dirty and i just put it back again.