Reviving an old thread, but I suppose it might be indicative of how little interest there seems to be in M's in-car systems. Anyway, as per topic, HiFi+ has a brief comparison of the high-end car manufacturers' offerings from the Geneva Salon de l'Auto here. Meridian's performance was judged a bit "meh", but what was interesting is the report that the company accept there is room for improvements and that these will be forthcoming "soon".

Main System: Trinnov Altitude 32-8-16, 271, 2 x 8KXE, 1 x 8KPP, 6 x M6 Surrounds, Rel No.25, Oppo 203, Zappiti Pro 4K HDR, Roon, WiiM Mini.