Anyway, if you downloaded a modified blockchain, there is no chance to lost your money with it, because if the transaction bradcast still works, the other nodes will verify if the transaction is valid and if you really have the sent amount, the worst case in this case is if the fake blockchain doesnt have your updated balance. (there is other problems too, but i think this is the biggest).
If you somehow download a malicious blockchain that is modified, your blockchain data will be different from others. You could potentially be tricked to seeing transactions that are otherwise invalid (with non existent) inputs. This is the potentially a serious problem when you're downloading a pre-validated blockchain from others.
If your client validates everything, then it isn't a problem. IIRC, there's a command that rebuilds the chain state only and I don't remember having to validate all the blocks again. I could be wrong, of course.