definitly get the o/r x, i used mil eliminators when i installed my x pipe so i had no issues w/ the computer throwing a check engine light, as for the sound, under full throttle it sounds awesome and i can tell a power gain, driving regular its still pretty loud but i tend to like it like that...finally, i dont think it made the sound deeper but i would say it sounds a little raspy but the o/r x basically just amplified the original sound of the car seing has how the car came w/ a catted factory x...