Yeah, this is safe...
"Safe" in this case meaning that you will not be physically harmed.
On the other hand, you will lose all your current Google traffic, lose all the rank, lose all the incoming links you worked so hard to develop.
Oh, and if you have lots of pages, Google will probably penalize your new site for having too much "duplicate content". The duplicate content penalty first nixes all the moved pages and, if there's enough of them, continues like a cancer to move through your site removing long-established pages from the cache.
But don't worry, automated Google penalties gently wear off over the course of a year or so -- so with a lot of hard work you can be back to where you started in only 6-9 months.