Bought a low mi 2014 4 in early 2020 after foolishly selling our red ‘11 4 with only 118k mi to ease move ME-FL. Was barely broken in/perfect inside/out. The 14 was not getting MPG we were accustomed to, so checked/replaced clean oil and found a K&N in air box. Was clean, but K&N’s screen was huge. MPGs came up indicating viscosity was culprit. Not convinced K&N useful in anything more than racing rigs?