no impact, those are friendly names.  Unless you are using vSphere storage plug-in i can't think of anything that would care if you changed the name.
I would like to rename some LUNS in Navisphere.  I am wondering if renaming LUNS when ESX hosts are using the LUNS will negatively impact anything?  I do plan on contacting the system administrator on the other side to have him rename his DATASTORS in ESX so they match what I Have in Navisphere.  Can anyone assure me that my changing the LUN names in Navisphere, if that will impact anyone?    Dont forget about all the other things its associated with like in RAID groups and what not.    Signed.... NOOB !! 
Renaming LUNS