The Ansa seems to have been the most popular option to minimize the "droan." Quite a few of the members have done the Magnaflow Cat Back and I believe the SRT-6 is a different set up than the NA for the Magnaflow. The key is several people complained that it was too loud between 2000-2500 under a steady throttle while others enjoy the sound. I believe there are clips of the Magnaflow posted on you tube.
Gary, has the ANSA as well as several other members.

Magnaflow in my opinion has a throaty racy sound, while the ANSA has a more euro sound.

The last and most expensive option is the Borla. On the Crossfire the performance gain is minimal and its more of tone change.