I recently looked through the code in the Banjo-Kazooie decompilation project to check how the minigames work and to confirm the amount of rubberbanding AI. So here's how Mr. Vile's maximum speed changes compared to the player's (rounded to integer percentages) based on your lead in the score difference. In short: Mr. Vile is only faster than you when you're leading with two or more points and don't use the turbo trainers. I could also confirm that Boggy rubberbands, but that one is more complicated and will take some time to condense into an image ๐ .
For anyone interested in the details: The code for Mr. Vile is in the BK decompilation project in src/BGS/ch/mrvile.c. The max speed is calculated in lines 376 to 386.
First it checks the score difference to set Mr. Viles base speed to 200, 310, 350 or 450 and then it multiplies it with 0.8, 0.9, 0.95 or 1.0 depending on the round. For comparison: the crocodile transformation's max speed is 375, or 500 with turbo trainers.
BTW, when you lose and he tries to bite you, his max speed gets set to 500 (line 413 in mrvile.c), so he's set to eventually outrun you even in turbo trainers.
