yes you can,
-> make sure psgrade exists for your TI device, if theres no .hex out there that works, you'll need a teensy or other compatible boards.
-> do not perform 3.55 demo firmware upgrade or you can kiss your demo console goodbye
-> jump from 2.30 or 2.50 to the modified 3.41 pup should be fine, you will end up with 3.41 retail with no BD playback problems.
-> from there, updating to 3.55 retail will enable PSN definitely.
they were definitely cheaper and bargainable before this exploit existed, now is a matter of whether the seller knows about it or not, nonetheless, the more people start converting the demo units, they will almost be non-existent for sale if ya know what i mean