Automobile(s): ('04 SRX N* AWD) '11 Lincoln MKT AWD
South Bend, IN
Ever since I ordered my SRX, I wondered the same thing---answer is: NOT!
As for "upgrading" firmware---these are not computers that you can download software and install. Only solution is after-market replacement or mps players "tapped" in or broadcast with FM transmitters.
Yes, it is theoretically possible that the SRX's OEM headunit designed to play CDA is firmware upgradeable to play digital media such as MP3 or WMA, but I highly doubt it. An OEM would have design and build the HU, and have coded the firmware to handle digital music in advance, and as there is low demand for this from a mass market perspective, I think you are barking up the wrong tree. If it existed, why wouldn't they have already deployed it? Take riff's or sgilbert's advise above.