What Takeingthe5th said.
I'd spend my money on comfort and convenience items if I had the money to spend. Maybe tire pressure monitors, back up cameras, 12V converter, 12V cooler, and I love my heated seat cushion/back rest in the winter.
Opinions will vary, but I would not consider a reusable filter. I tried one and prefer to change filters rather than try to clean and then get the correct amount of spray on the KN or similar reusable filters.
You might save some money over years of use but the time, effort and piece of mind is better with a replaceable filter for me.
Almost forgot to mention the Mass Air Sensor. Clean it, the biggest power boost for my old Astro van was after I cleaned the MAS.