richms:

 

all good till the velcro let go and it started sliding around in the boot hitting the sides. That killed it.

 

HA! Happy to stand corrected!

OP - I installed a bluetooth headunit in my car and love it! Definitely better audio quality than using the audio jack on the old headunit, obviously with the same speakers etc. Also as far as spotify goes, you could look to make stuff available offline but this is of course a hassle.

You could of course get something like this - much less likely to get knocked around but limited to 64GB which it sounds like would be too small for you.

https://www.amazon.com/SanDisk-Cruzer-Low-Profile-Drive-SDCZ33-064G-B35/dp/B00FJRS6QY

Would a 256GB usb stick be enough? I see they are on amazon for $76US. The other hassle if you go for a 2.5" SSD is where do you put the thing? A stick would be much more convenient.