For what it’s worth I suspect that many of the clones come out of the same factory as the originals.
Not sure if you mean same as V.W, but certainly there are loads of Chinese clones with different marketing, options and the same type of guts. I've been inside mine a couple of times. Any more going inside and I'm worried parts will be breaking! They use a single mother board and attach the various modules in a cube fashion starting with the front panel. This is how they can seemingly all have different options at different prices. I have a DTV tuner and DAB radio in mine, they are just a couple of modules linked to the motherboard. The cube physical design makes it really hard to work on since some of the upright boards are hard soldered with a ratsnest of ribbon cable joining everything up.
The original V.W rf antenna diversity if they still use it is really clever. They use a special Philips (?) IC chip which duplicates two I.F channels, then they detect and level at I.F to avoid the need to do it badly and noisily at r.f. Lack of decent diversity on my clone means it can't hold weaker stations well. I once toyed with installing an external antenna and the only place I thought would work avoiding roof collisions was the center of the windshield section just forward of the sunroof. But I was too scared to start drilling a hole then have it go rusty around the antenna mount. Now I listen mostly to MP3s which are interference free.
I did have some issues with processor noise hash pickup affecting the satnav antenna and FM radio. Of course this gets worse with weak reception. I fixed some of that with screening, power line filters and some extra caps on the internal power lines.
My clone like most has seemingly quite comprehensive E.Q. controls. But the flashy screens are not what they seem. If you want the kind of true bass you can get with Dynaudio you need the power amps and speakers to match. The clones will spec. their audio output power at some distortion level, but you won't be able to sustain loud clean bass boosted by several dB. The Chinese have learned to limit power output gracefully as their boxes heat up or switch on a noisy fan and hope you won't notice.
If you mount the PA separately under the seat, you can get decent power. Although all that size has now changed with digital amps. I'm o.k with them for bass, but not above 100Hz.