I have pondered this question and am curious if anyone would know. I like to travel with tons of music (normally 600+ albums) and have pondered putting in a larger hard drive into the radio to prevent having to keep multiple USB stick in the center console. It would appear that the stock HDD is around 32 GB as I can put around 25 GB of data into the radio and that would leave some room for the software for the nav and whatnot.

Sure, I could go with something above the 32 GB USB sticks I am currently using, but I have found going above 32 GB results in a long time for the radio to sort out the music and figure out where it is before the radio starts playing music. Looking to improve this. Putting stuff in the radio makes the loading of music happen quicker.

Can the system handle a bigger hard drive? If so, what is the max?

 

You can add bigger HDD or even indGrade SSD with PATA to SATA adapter. (if your system is still with PATA drive) However, it might not help much If your system are still Gen 2.1, because its limited max partition size is under 32GB by QNX OS. Not sure for newer systems.
The HDD are locked by ATA password. Without it you canīt read and copy it to the new drive. (the drive have software installed, so if you just install empty drive, the system will not work)
The password(s) are spread and its quite easy to take image from existing drive and copy it to another using exsample desktop PC with Linux (USB live boot will do fine)
Its also possible to rescue un-finished/bricked map update. (done it twice)
Hint: Volvo used same unit and there are threads on Volvo forums discussing about HDD chances etc...