I have a 2003 sedan without the sat button. I have the bose premuim. I want to install a phatbox without fm mod, is this possible?

 

It should be possible, because by default the Phatbox comes with the CD changer firmware and you select it by pressing the CD button and it will switch from the in dash changer to the Phatbox. Since you have the 2003 make sure when you order it you ask for them to send the cable that goes to the back of the head unit instead of the short cable meant for those that have the SAT prewire. It is a pain to run the cable but there is a very detailed step by step process on G-owners.com which will help a lot. I followed it to install on my car.