I've read about not being able to "patch" etc on the newer models and some don't come with an SD slot anyway so I'm lost as to which models to look at.

I use a sat nav for my job as a hgv driver so have been using truck maps on an SD card in an old unit which is slowly giving up on me so looking for a new unit. Not keen on forking out for the tomtom official truck ones as I don't use it that often and I don't know if they can be switched to car mode. Ideally a model with 64mb ram to run the latest maps/navcore but most listing don't mention the ram. Any suggestions of which models would be suitable? Don't mind 2nd hand ones but was thinking new to give peace of mind and longer life span etc. Guessing the maps and navcore that I've downloaded through the forum are the same as what is on the tomtom truck models as the screenshots I've seen are totally different.

Thanks
Mark.

None of the newer models built after September 2012 are able to use downloaded maps or navcores etc...read this

If you want to buy a second hand one to do this, we usually recommend models like a Go x40 or x50 as they have 64MB RAM and have an SD card slot too