any oil designed for a gauze/cotton air filter will work, just some work better than others.

 

You should get a Cold Air Intake System. You would get some more power and torque. I would recomend K&N. I'm not sure if they carry them for your truck?
You should check. They also sound cool. You can here it at about 2,800 RPMs.

 

the k/n intake is overpriced, many others are offered much cheaper. They will all give you the same results, some by price or brand preferance.

 

k&n will be a bit more expensive because they have been around longer as far as i remember

 

I would recomend K&N. Its worth it.