I'm missing the roundness of the car in #8, yet #10 has a nice addition of the books (up to my ears in books is a great idea!). Black (or one color) On-The-Go lettering would be preferable to (in my limited opinion) make the primary colors of the books stand out more.
Re: #16 and #15 I'm not seeing entry #15 where you said you changed the lettering to all red. The car is improved, but the green lettering in #16 is too dark/harsh. See the green in the laurel wreath by your name (where the 85 is underneath). That's more of a green I'm interested in, rather than primary colors.