So I recently installed a Spectre cone filter on my 2012 Elantra with a redcuer onto the stock piping and noticed a small difference on my gas mileage. At first I thought it was because I was rippin' it to hear that awesome sound I got from it, but today I filled it up and reset the trip. Even after I babied it all day and drove on ECO it showed 16 miles exactly when I lost a gallon. Any solutions about why my gas mileage is terrible? Or should I keep watching it? Things I have read on the Veloster forum with the same mod I did showed that it increased gas mileage. Am I just being paranoid or is it really screwing up the mileage?