I am in the same situation. Renewing your PR would take almost same time as your Citizenship application. You will just spend more money for no reason. PR would only help you to re-enter to Canada if you leave. Something I won't recommend. Be advised that you have signed "Intend to Reside" clause and it is not recommended to leave Canada during time your application is in process.
Here is the official CIC website talking about this: http://www.cic.gc.ca/english/resources/tools/cit/grant/residence/intention.asp
Here is the quote:
"For brevity, throughout this program delivery instruction, the term “intent to reside” will be used to refer to the intentions referred to in paragraphs 5(1)(c.1) and 11(1)(e) of the Act.
Subsection 5(1.1) of the Act states that for the purposes of paragraphs 5(1)(c.1) and 11(1)(e), the person’s intention must be continuous from the date of their application until they have taken the Oath of Citizenship.
Officers will be assessing the applicant’s intention if granted citizenship (i.e., what the applicant intends to do after becoming a citizen). Applicants must hold this intention to reside if granted citizenship from the time they sign their application to the time they take the Oath. The intent to reside is required to obtain citizenship but no longer applies once citizenship is granted. Once citizenship is granted, a citizen has the right to enter, remain in, and leave Canada as guaranteed by the Charter."
I would recommend being very very careful with this issue. Considering all these, I think you really don't need to apply to renew your PR.