here's my $0.02...
on MAF sensor equipped cars (like the ATS) .. DO DATALOG! the ecu is calibrated for a certain intake, and piping diameter, it knows how much air flows through it.
change this, without logging and/or tuning, and you're gambling. the ecu will not magically adjust to the new intake, as it doesn't know anything about it, all it does is measure airflow.
however, a properly designed intake, can be used on a stock ecu without problems.