As a follow-up to my previous post about the addition of the LTZ dual exhaust to my '98 3.1 Lumina... I just filled my tank up with gas, after doing some significant driving. The fuel efficiency has improved by ~1 mpg. This is pretty impressive, and I'm wondering if the computer has a teach capability that will improve vehicle performance when you do things like uncork the exhaust, improve intake performance, etc. Anyone know?