I use Tails(Standard) for Drift Events. It makes getting expert pretty easy. (The House of the Dead one wasn't so easy lol but the last jump on that event is a good spot to get the Virtua Trickster achievement)
I just got all 232 stars yesterday and these are the characters I used for the events.
Traffic attack - For the Panzer Dragoon stage, I use Amy standard. For Shibuya Downtown, I use Metal Sonic boost mod. Rest of them I use Amy handling.
Drift - Tails standard. However for the House of the Dead drift event, I used Amy handling.
Race - I prefer to break race down to 3 class of tracks fast, normal and twisty.
For fast tracks, you want a character with good speed etc BD Joe. For normal tracks etc mixture of fast and twisty sections like the Shinobi track and Graffiti City, you want a balanced character etc Knuckles, Avatar, Danica Patrick, Nights. For twisty tracks like Billy Hatcher, pick Tails or Amy. You do not need to have special mods for races. Just choose their standard mod and your good to go.
Boost race - For boost race I use Metal Sonic boost mod.
Boost events - the same rules apply as if in a standard race. Fast, normal or twisty.
Ring race - I did all ring events with Amigo standard mod.
Versus and sprint - same rules apply as if in standard race. Pick character based on track type, fast, normal or twisty.
Pursuit - Any character who is small, has decent acceleration and good handling will be great for pursuit. I used Amy standard for all my pursuit events.
Driving a PC racer with the keyboard is about as effective as typing an e-mail with your car's steering wheel. ~ Brian Ekberg