No, you'll be fine,the new 7.8 will overwrite the old 6.1 version without deleting anything ( 6.1 is too old now, you'll find a big improvement in 7.8

)
Also make sure to use the same package used before (LAUN12345 or LAUN12353) so it will overwrite the old manager, normally it's LAUN12345.
thanks mate...
This depends on your "games" folder location, with Rogero 7.8 you can change the selected "games" folder from the settings inside the manager, you can select from a list of paths the folder you want to use for games.
A good thing to do, if that you move the games folder to a safe path like "dev_hdd0/game/games" independent from any manager (you can use BlackBox FTP server to move the games folder)
games folder u mean the internal of the ps3 not the GAMEZ folder if u have a external ryt??
yes, no problem at all,just make sure that you use a "games" folder path compatible with Gaia then you can load the same folder with Rogero 7.8 by simply changing the settings to use that same folder.