Design #19 -- Several intriguing aspects of this design. Seems that the shield and motorcycle silhouette leans too heavily towards the Ducati brand.The multi-tone gray parts of the shield add a rich dimension to the textual description. Don't really care for the bowtie (?) text effect.
Design #24 & #30 -- I like these designs, though text is hard to read. Perhaps a light rectangular banner under the text and on top of the shield will provide the right amount of contrast and separation for legibility.