You are making things very difficult for yourself. First, why do you have a seventh level for free trial members? I'll assume it is because you aren't really giving them a "free trial" of all your content, but if that isn't the case I really would like to hear it.
s2Member is equipped to handle free trials "out-of-the-box" without jumping through hoops (and you can't say that about everything with s2Member, as much as I love it). It is not equipped to do what you are asking "out-of-the-box".
There are several threads in this forum about logging in new Members automatically after registration. Try the Search icon at the top of the page.
Given that this is exactly what you want to do:
- Register as a free Subscriber
- Fill out a Billing Modification form for an upgrade to Level 7 for 14 days
- After 14 days demote to Level 1
Then the answer is this cannot be done without custom code. However, if you are actually offering people a free trial with access to all Level 1 content all you have to do is have them fill out a Level 1 Registration Pro-Form with a 14-day free trial.
No, and since you say you are using PayPal then it couldn't be done even if you wrote custom code because PayPal has a 25% limit on price increases for existing subscriptions.