i have an 01 mustang gt, 113k miles, i got it with 93k, didnt smoke or use a drop of oil. at about 100k i put upr o/r x pipe on it and as soon as i started it up it was smoking, not bad but it was. every since then its used 1-2 quarts in between oil changes. and people who follow me say when i switch gears smoke puffs out. what would make it start smoking just from putting on an x pipe?