All of them are hackable. The limit is, as you rightly point out, the internal memory.
If you just purchased it new, you might as well first use the 30 day latest map guarantee before modifying it in any way. After that, you can safely store the legit config that you have, for example zipping it on your PC. Then you can start playing with SE Navcores and patched maps.
Try navcore 8.562 or 8.417 SE for a start. If you grab a full "deluxe version", you might need to prune it a little bit (remove extra voice files, raster maps, LoquendoTTS folder, \art\cars\ contents etc or it might not fit.
It is actually a refurbished unit and the map updates are expired. I will try to call tech support and re-enable the updates. If it doesn't work, I will probably return it.
Dell.ca has the XXL 540M for sale, which has lifetime updates. Would that be a better choice?
From what I've seen on the forums, "lifetime updates" is limited to whatever the company feels like.
Does anyone have any experiences with these so called "lifetime updates"?
I'm not Canadian, so I am not familiar with the "lifetime Update" feature. In Netherlands though you have a 30 day latest map guarantee even on refurbished models. Doest it actually tell you that this is expired when you select TTHome > Menu Tools > most recent map insurance (or something similar in English)? I would call Tomtom for clarifications.
I have the tomtom XXL 540-M which has the lifetime maps. I got it for 90 which seems like a decent deal. I'm just trying to figure out (from reading threads on this forum) if it's worth hacking it or not. I mean i already get the newest maps and I can download voices and they work. I couldn't find a thread where it has the actual benefits of patching the navcore (but i guess it depends on your model).
with any of the new models that end in M, you get lifetime map updates (4x a year). The only reason at that point that you would want to patch the navcore is if you want to install 'official voices' from here. Voices that don't need patching will go in your unit without problems.