Putting on the front mount now won't do any harm, you might see a little increase in power, or none at all. But it won't hurt and it makes more sense doing that first to save on tuning costs, so you are thinking right imo.
On the subject of doing it all at once, i wouldn't recommend it, as you'll get used to the new power just the same, better off doing it in increments as you feel the power gain through each mod, and seem to appreciate it alittle more. Just my 2 cents.
The S-AFC-2 has the knock sensor, more adjustment rpm points (8v12) and you have smaller adjustment increments of 200rpm, instead of 500rpm compared to the S-AFC 1 I believe. I just recently got my S-AFC 2 (new) through nengun, $420 this includes shipping to my door.