http://ds.ign.com/articles/117/1174809p1.html
Apparently, the mini-turbos are going to be somewhere in between Mario Kart DS's and Mario Kart Wii's. They will automatically turn blue, but you'll swivel the control pad to upgrade them.
I'll update the OP tomorrow with the new news!
Does anyone else wish that the makers of Mario Kart would use tracks from Mario games? I mean, I'm all for tracks like Waluigi Pinball and Maple Treeway, but for once, I'd like to have some nostalgia. Luigi's Mansion-esque tracks, a track based on Rougeport from Paper Mario TTYD, or maybe Bob-Omb Battlefield from SM64. I think that would be awesome.
I'm pretty sure that many of the tracks are based off of Mario games:
-SNES Donut Plains 1-3 were based on SMW Donut Plains
-SNES Choco Island 1-2 were based on SMW Chocolate Island
-SNES Vanilla Lake 1-2 were based on the peak of SMW Dome in the winter time.
-64 Choco Mountain is based on SMW Chocolate Island
-64 Sherbert Land is based on SM64 Snowman's Land's ice paths, while the penguins are from SM64 Cold Cold Mountain
-64 Royal Raceway, of course, has the SM64 courtyard
-SC Has a Paper Mario cameo in Rainbow Road, as well as elements that are present on the path to Shooting Star Summit. (the falling stars)
-DD Peach Beach is a Delfino track
-DD Dry Dry Desert is a homage to Paper Mario
-DD Luigi's Mansion is completely inside the building with the same name
-DD Cookie Land is a reference to Yoshi's Cookie
-DS Luigi's Mansion occurs in the same building
-DS Desert Hills is based on SMB3's world 2, complete with the Angry Sun and fire snakes
-DS Delfino Square is in Delfino Plaza
-DS Tick Tock Clock is based on the SM64 stage of the same name
-DS Airship Fortress is a SMB3 fort being invaded by an SMB3 airship
-Wii Mushroom Gorge is based on the levels in NSMB that had bouncy mushrooms
-Wii Maple Treeway is based on SMG's Gold Leaf Galaxy
-Wii Grumble Volcano is based on
World 8-8 in New Super Mario Bros.
-Wii Dry Dry Ruins is another reference to Paper Mario with music based off the Yoshi's Story theme
-Wii Delfino Pier is based off of SMS' Delfino Plaza
-3DS *unknown jungle course* is based on the ruins in Donkey Kong Country Returns
I'm sure there are some others, but those are the references that were more noticeable to me.
EDIT: Here's a nice video with clearly audible music:
http://digitalchumps.com/gamingnews/1-latest-news/7625-impressions-mario-kart-3ds.html