What modifications (custom or factory options) have you made to your C6?

For bonus points, post a picture of your change(s)!

I don't think you would call this a "Mod."  It is a DIY cup holder for my C6.  I mounted two folding cup holders on a piece of sticky-back felt covered aluminum.  I like the way they fold up and have been using them in my RV for years.  They are usually found at camper and boat suppliers. 

Did you also add some LED lighting? The floor lights look purple in these pics.

Yes, I added the blue LED light kit for the floor area and the trunk of my convertible from the National Corvette Museum store.  Easy install.