Here is the proper explanation about "symmetry". The first thing you should do is to make CarBlaster display byte values in hexadecimal (press Shift+H), it makes everything much more convenient. Now, if you go to the 24-byte section of (random example) Acura, you'll see the relevant values are arranged as pairs of bytes. The first of these, the x coordinate for the front/left corner, has values 40 and FC (in hex, which I'll indicate by appending them with 'h'). The pair, however, is supposed to be read as a single number; and to do so you invert the order of the bytes. Thus, 40 and FC become FC40h = 64576 after converting to decimal. This is the first subtlety. Of course, 64576 is a ridiculously high value - and then comes the second subtlety: very large values (above 8000h) are in fact negative numbers stored in a convenient way. To recover the original number, subtract the value you got from CarBlaster from 10000h and invert the sign. In our case, 10000h - FC40h = 3C0h --> -3C0h = -960, which is the value we expected to find. Now, if you jump six bytes forward, you'll see the values for the x coordinate of the second (front/right) corner are C0h and 03h, thus the coordinate value is +3C0h = +960 - symmetrical to the front/left coordinate, as it should. Applying the same principle everywhere, once you settle for values of half-length and half-width for a sane rectangular car, the pairs of bytes should be set like this...
1st (front/left) 2nd (front/right) 3rd (rear/right) 4th (front/right)
x-coordinate -halfwidth +halfwidth +halfwidth -halfwidth
z-coordinate +halflength +halflength -halflenght -halflength
...with the negative values being stored as (10000h - (your absolute value in hex)). If you are just messing around with values/doing quick tests, the easiest way to keep track of the changes is to, every time you add to a x-coordinate byte, add the same amount to all other corresponding x bytes (that is, the ones 6, 12 and/or 18 bytes before or after) with the same sign and subtract the same amount from the ones with opposite sign, and vice-versa for subtraction, and the same goes for the z coordinates.
And about your replay: zOMG
It seems your car did reach the outer space, and when it happened the world flipped over and you hit the ground - from below
And what's more, I had seen crazy stuff while testing the parameters but levitation from a standstill is a new one for me too - it's a must check...