Free App to Paid App and back to Free...Does it work? App Sites pick you up?

[matador1978]

Hi guys, i was wondering:

If you release your app as Free, leave it Free for let's say a week or 2, then put it as Paid and then back to Free again after some time:

Is that allowed?
What happens to the ranking in Free? Let's say you are at position 100 before you set it to Paid. When you go back to Free after a month or 2, do you start from scratch again, or ...
What happens to reviews? Do they get lost in the switch?
Do you still get picked up by App sites and bots when you switch to Free and have a download increase?

Thank you for taking the time to help.

Cheers
Chris