Load runner 12.02 to Performance Center upgradation

Hi Experts,
Hope you are doing good. Currently, We are using Load runner 12.02 version , ALM 12.02 and would like to upgrade to LR 12.02 to Performance Centre latest stable version?

1 Load controller server [WINDOWS 2008 R2 64 bit SP1] and 4 LG servers [WINDOWS 2008 R2 64 bit SP1].

Please suggest the check list and stable Performance centre version to avoid any potential issues.

Q1) Are there any issues reported for 12.53 since it is a new release? Which is efficient patch # for 12.53?
Q2) Are there any unsolved issues reported for 12.53 since it was released? Which is efficient patch # for 12.53?
Q3) What are the additions and eliminations done in 12.02 to Performane Center 12.53
Q4) What are the steps we have to follow for upgrading Load runner 12.02 to (performance center 12.52/53)?
Q5) Did anyone face challenges while upgrading from Load runner 12.02 to PC 12.52/53. Is it documented anywhere by Vendor for reference ?
Q6) What are the pre-requisites (database backup/admin access to repositories etc ) we have to follow before performing this version upgrade of LR 12.02 to 12.52/53?
Q7) Where from we have to download the new version software’s and patches? will vendor provide appropriate software after studying our Infrastructure?
Q8) Will the Version upgrade from LR 12.02 to [ 12.52 OR 12.53 ] affect the ALM 12.02/ Performance Center/ Load Runner Licenses?
Q9) Should we request for Licenses for ALM/PC after the Upgrade?
Q10) Will the old scripts present in LR 12.02 get executed on PC 12.52/53 OR do we need to upgrade all the LR 12.02 scripts to 12.52/53?
Q11) Should we use any upgrade tools like QTP Asset Upgrade Tool for Upgrading Scripts from One Version to another?
Q12) Which Patch Level # is most efficient/recommended by vendor for LR 12.02 and PC 12.52?
Q13) Should we upgrade IE on client / server or is it not needed. Currently we are on IE9 & 10?
Q14) After Upgrade should we inform users to install any pre-requisites before accessing this new PC 12.52/53 release URL ?
Q15) Is there a mechanism where we can load all the client side perquisites in one location of PC site, so that all users can download from that location onto their client machines by accessing PC application?

Please share your valuable thoughts from your past experiences on this version upgrade.

Your help/guidance is appreciated.