When the VW Golf mk. 5 was released it had a very good standard audio system but they seemed to row back pretty quickly, probably to either cut costs or make room for a premium upgrade (or both). Saab used to be pretty good for fitting good quality audio systems.
My Audi A6 has the standard fit audio system that goes with S Line trim, it works but the infotainment system is very slow and SQ not great.
I was amazed a few weeks ago when I was looking at Hyundai and saw they're sticking the Krell name on their upgrade stereo systems now.