2005 mazda 6 3.0 manual

Hey 1st gen owners. I just purchased a 2005 Mazda6 wagon (GT edition with Bose sound and 6-disc CD changer) looking for advice on a product with aux cable (Iphone lightning) or bluetooth that is relatively easy to install (i.e. I would prefer not to have to solder anything). Looks like Synflex...

does anyone know if i can get around paying close to 1000 dollars to replace the "4" catalytic converters? can I delete them? is there a way to flash the computer? someone... anyone ... plz help