Ok, I've been watching the speed address for MKSC (thanks for finding it again fried), and have come up with some basic information on all of the characters, involving top speed with shrooms, mt's, and normal driving.
Ok, so here it is.
Top speed (Normal)Bowser - 1102-1104
D.K - 1098-1100
Wario - 1094-1096
Luigi - 1092-1094
Mario - 1090-1092
Peach - 1086-1088
Toad - 1086-1088
Yoshi - 1084-1086
Top speed (Single MT)Bowser - 1282-1284
D.K - 1278-1280
Wario - 1274-1276
Luigi - 1272-1274
Mario - 1270-1272
Peach - 1266-1268
Toad - 1266-1268
Yoshi - 1264-1266
Top speed (Shroom)All characters - 2016
Ok, now for some basic explanation.
The normal top speed oscillates between the three numbers (In Bowser's case 1102, 1103, and 1104) in a specific pattern.
The specific pattern (in Bowser's case) is 1102, 1103, 1104, 1103, 1103, 1104, 1103, 1104. (replace the numbers with the specific characters numbers to see the pattern for them) When it reaches the last number the pattern repeats itself.
Now, the top MT speed doesn't actually change in itself, what changes is the timing that you release the MT. If you release the MT on the frame where you are at the highest speed, you will get the highest speed out of your MT (in Bowser's case 1284).
Your odds for hitting each specific speed is as follows:
Fastest MT speed - 3/8
Average MT speed - 4/8
Lowest MT speed - 1/8
Finally, as you can see in the Shroom speed, all characters have the exact same top speed for shrooms!
Going by this information, all characters are relatively fast, but the some characters are totally useless, such as Yoshi, Mario, and Wario because their counterparts are faster. (lightweight, middleweight, heavyweight)
Well, that's all the information for now. Fried will probably bring you more in depth information tommorow. Ciao!
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Michael F wrote on 01/26/08 at 13:54:58:I made a new discovery today about MKSC... The programmers were on drugs!

The acceleration in this game is totally messed up. Each character reaches its peak acceleration at a different point in time, and every character accelerates the fastest at some point in time! Toad starts out accelerating the fastest, but once he gets close to top speed, it takes him a very long time to get all the way there. Bowser, on the other hand, starts out accelerating the slowest, but once he reaches a decent speed, he accelerates the rest of the way very quickly. Here's the excel sheet I made that lists the acceleration, speed, and distance for each character at every frame up to 7.76 seconds:
http://wrvids.com/Mario%20Kart/MKSC/Other%20MKSC/mksc%20acceleration%20data.xlsAnd here are 2 of the graphs I made (this is all without the rocket boost):