The build issues are all over the forum and every courtesy car I've had has done it. You even hear it on loads of youtube vids of people posting 0-100 times etc. All made worse by a bit of bass. It's a shockingly poorly put together car in my opinion.
Not saying you're wrong (and you have a Leon and I don't) but it's common for forums to be full of posts on car issues / problems.
Posting "Got in car this morning, it started without
problem, drove to work without any issues . . . . , etc." would get pretty boring reading in a forum!
Can't comment on the sound system, though I would order it. And will do so, if Seat UK pull their finger out and give us the option of Dynamic Chassis Control on the FR 180/184 that they keep telling me will be offered once the
Cupra has been released. I've been told this a couple of times from customers services in the past month alone