If you have a raised foundation, maker sure you have proper support under the floor. Maybe had a few piers and extra supports depending on how large your safe will be. Slab floor no issue.

Most safes have the locking mechanism is the same place. Intruders know this and can drill to a templete and open your safe. My safe has a feature I like. They place mechanisms staggered around in the door. Your serial number corresponds to a map location that they keep. Makes it a bit harder to penetrate.