Gutting your airbox won't do you any good unless you buy a K&N replacement. It'* all budget related. If you can afford the ADTR intake, buy it. Nothing better. If you can't, then gut your airbox, punch some holes, run some ducts, etc. It'll help. I wouldn't advice removing your MAF screen if you go this route. Wait for a custom intake with a cone filter before you do that.
You basically want to remove anything unnecessary in the box that will disrupt airflow. I'm not familiar with the Series 2 box, so I can't get specific.
I'm not a fan of stop leak of any kind. Keep an eye on the fluid level until you can get the PS fixed the right way.