Whilst it is true you can apply for PR during Implied status (given your visitor record decision is pending); it is a risky move to send off for PR. i'm just curious on why you wouldn't send in the OWP along with the PR app as if your visitor record is declined then you are considered out of status and you would have 90 days to restore from the day of refusal. You don't have to leave canada immediately, you just have to apply within those 90days, if you don't then yes, you will be told to leave. However! There is an option called "public policy" which can help to stop you needing status with inland PR, least from what I told on the phone by the CIC but again, it's not guaranteed.
From my own experience of applying for a 2nd visitor record (extension) it is generally not accepted as they will see your sponsorship application and decline you based on that verdict as you are considered "not going to leave canada" even though it's obvious what PR is.
If you applied for OWP with the PR app; and it is accepted, then that generally lasts for 2 years and you get implied until the decision is made which is generally 4months from that. It just might be less stressful for you?
Anyways, hope this helps in any case?