Red brick car is intended!
I swapped out the RC car as balancing the stats for that vehicle just won't happen because of how the car is in general. Any increase to its speed will just cause it to spin out and be almost uncontrollable, so I instead opted to swap it out and use the Red Brick Car instead.
Generally, for the main level cars it's +10 and for some of the purchasable/unlockable cars I think they were mostly in the +25/40 range in the speed stat. I have listed the difference in the stats for the cars so that wouldn't be too much of an edit to make at all.