First of all, I'd like to say that I'm a big fan of romhacking.
You store in this site really precious jewels.
Then, I'd like to suggest a simple but significant hack for this title - Biker Mice from Mars
- wich I consider to be the best racing game on the Super Nintendo. It has the best elements of both Rock'n'Roll Racing and Mario Kart, so I found it to be the number 1 in matter of racing games.
The suggestion is that you alter the "Main Race" mode, so when you destroy an opponent in a race, he stays destroyed until the end of this race (the same should happen for the players, if they were destroyed).
If we select "Battle Race" this already occurs (if you destroy your opponents, they would stay out until the end of that race). The problem is that, in Battle Race, if you're destroyed in one single race, it's game over. And if you select "continue", you lose all the upgrades you bought for your vehicle.
So, this hack of mixing these element of "Battle Race" with "Main Race" would be highly appreciated. Unfortunately I couldn't make this hack, because I'm not a programmer. I wouldn't either know where to start...