Across answers are entered normally. Down answers must be altered before entering and will not form words in the grid. The center across will reveal a message that would be helpful if I gave it to you before solving and what you may want to say to me after. (No enumerations as all acrosses are 6 letters and downs are 7 - there is one multi-word answer)
Hint: The numbers for the down clues are key to their transformations