Thanks FatRatKnight and Memory for the research and videos regarding brake tapping. It's something that's passed my mind before, but have always dismissed as being too difficult to do. That's mainly because I've perceived the machine's speed oscillation as being affected by the different terrains in the game (mainly talking mud and electricity) and I can imagine the scope for screwing up brake tapping is magnified by those terrains. Given when you're boosting you're trying to touch track limits as often as possible for maximum tightness (and making the most of the lack of speed loss), those instances are more often than not. I could very wrong on that front, though.
Regardless, trying to incorporate brake-tapping, as FatRatKnight says, while snaking and doing drift-extended boosts would be quite the challenge! But regardless of brake tapping's RTA feasibility it'll be fun to see in this TAS.