New car - Audio upgrade (Golf 7.5)

[tjdixon911]

I'm due to pick up my new car soon, my outgoing Leon has the "seat sound" pack (sub in the spare wheel, upgraded speakers?) - the new car doesn't have the VW equivalent (dynaudio) so I was wondering if there was a relatively cheap way of upgrading.

Would the addition of an underseat / spare wheel sub do the job or would I need to add more? Are these best left to the pros to install or are they easy?

Any help l, much appreciated.

New car is a Golf 7.5 estate.