Spoon Snorkel, replacing air filter
 

What's the best filter to replace the stock one in the stock airbox.

I have a spooner snorkel extension on it.

Don't ask me why I typed "Spooner" :LOL:

For future reference, you can go back to any of your posts to edit something or add something (like a picture). This will make doing 3 posts in a row unnecessary.

As for the filter, since you haven't really changed anything in the stock airbox except for where the air originates, there is no need to change the filter unless you want to.
The OEM filter works quite well but you need to keep replacing it when it gets dirty. If you want re-useability, some people have gone to a K&N insert or a JR insert (which is like a K&N but some say it's "better").
When deciding which filter you want, you need to consider not only "re-useability" (cost) but you must also decide whether you want better filtration or better flow. In general, you can't have both. So, when you ask which is "better", you have to know what you want. The OEM one is better for filtration. The others are better for flow.