Teleport works fine either on Tweaks and not-tweaked server. You wont get OOS when the teleport distance is not far, on non-tweaked.
For Z axis, you can simply define a max value that user can reach, and program a kick/ban/whatever you want if the player go beyond this point.
For X and Y, is a bit harder. As I said, big jumps are caught by LFS. With small distances, you need to calculate user's speed using the difference between initial position and final position, according to the scale you use X and Y. Remembe that 65536 on MCI packet, without scaling, means 1 meter.
An example of the idea: Initial X is 0, and after 1 second, the X is 9175040. This distance, divided by 65536 is 140. So, the player moved 140 meters in one second, with means 500 Km/H.
You can have different tolerances to different cars. Also, just a tip to you: consider using a timer to monitor the X and Y. During crashes, the car flip around with 200, 300 or even 400 Km/H (I already tested a lot of times to implement a anti-cheat on my server... believe me
).