[leong124]

I can hardly think that it is a bug in GTA:SA.
If it is a GTA:SA bug, you should see your vehicle explode, but actually you are not.

Also, you can still see the vehicle health without overflowing (in that case you will see 65536.0 instead of some other negative values). For comparison, the player health will overflow with a period of 512 health units (-256 to 255), but both yourself and other players will not see you die even if it is overflown. That means both sides are the same(as all copies of GTA:SA are the same, except those cracked versions). In this case, it is not.