Yep, it's a start button, and I guess 03 Bose came with tape decks.

 

the 03 and 04 coupes and sedans had tape decks. for 05 they got rid of it and gave the cd player mp3 playback.

I haven't used a tape deck in over 10 years, I wish I had an mp3 CD player instead!!! poor market research by Infiniti, I think even older buyers only have CD's nowadays.

 

great pics... 2 very nice lookin cars you got there.