I've read some posts indicating that, after adding certain mods, the engine might be running too lean and a ECU upgrade is needed. I'm plotting out my future modifications and want to know when I should upgrade the ECU. As with most mod plans, I'm going to add things slowly as money and time become available, so it's not like I can just add all my parts and get the ECU upgraded at the same time. What's the best path - intake, plenum, exhaust, ECU? Or should I get an ECU flash in the beginning for my anticipated mods? If I do wait for the flash, what are the possible ill-effects on my engine by running too lean? Anybody have any knowledge on this? How about my current mods (Ztube/K&N) is that causing my engine to run lean - am I doing damage?

-townsley-
2003.0 Premium BS/Willow 5AT Sedan
ZTube/K&N Filter/Sport Suspension
Grounded/Tinted/Splash Guards
Lip spoiler/Aluminum Pedals
Battery Disconnect Switch