A buddy of mine just installed a CAI and was told to reset his ECM for the change in air flow over his MAF sensor by disconnecting his battery wires and letting it sit for about 10-15 min. Does this really reset the ECM and if so is it necessary?

 

It's not absolutely necessary as the computer will eventually adjust, but it's not a bad idea and doesn't take much effort.

 

So I got everything installed & reset the ECM but during the install I wuz short about 4 inches of wire for the O2 sensor in the intake pipe so I had to swap everything around, now the O2 sensor sits in front of the MAF sensor, is this gonna mess anything up or reduce engine performance?

 

It is not an O2 sensor, but rather an Intake Air Temperature sensor. It should not matter where in the pipe it is.