If your car is N/A, stock heads, intake, stock exhaust manifold? Bigger is not always better, as there's a reason the stock motor was designed with the "OEM" 80mm MAF airbox. Although the 2008-09 Shelby GT came factory installed with the Ford Racing/Steeda 90mm CAI, even with custom tuning, the stock 3v motor never the less is only capable of taking in the amount of airflow for which it was originally designed. Therefore anything over 90mm MAF on a stock 3v motor is considered as overkill and useless. That being said, unless you've upgraded to mods that can take full advantage such as high-flow heads, intake, cams, LT headers or FI that actually benefit and require more airflow, you're just far better off sticking with your Steeda 90mm CAI IMHO!