WOT or high rev (anything over like 4500RPM), the A/F meter reads "rich" (somewhere between the 1st green LED and the last green LED).
The only time it reads LEAN or shows any red LED is when I let go the gas, stepping on the gas suddenly (the red LED shows only for 1/2 sec), or idling.
I don't think you have anything to worry about by putting new intake or exhaust.