Thanks everyone for your responses . . . I reinstalled the stock airbox, and what a difference!!! I should've never spent the $ on the K&N filter for it made my engine run hotter, rougher, and louder. The turbo sounded cool, but got annoying after a while. I never thought it would make that much of a difference, but anyone who's reading this, and is thinking about swapping the stock airbox for a K&N filter, I wouldn't recommend it, at least for an 85 300d Turbo california edition.