Originally Posted by
Doppel
You don't need to elite pass all A+ challenges to get "Elite Completist". A+ and Prototype challenges don't count towards it, but you'll need to Elite pass all prototype challenges for "Prototype".
Good news are you only need to elite pass a single race to unlock "Speed Thrills" trophy.
I think Sol is probably the easiest track to do it. Here's my video and it wasn't stellar by any means. I played it very safe, only taking the last shortcut.
*video snipped*
Note that it seems like AG-S Speed is actually the fastest in A+ class despite the stats. You should definitely give that ship a try if you're having problems with AI straight up.