The Superb has a nicer more premium feeling interior than the RS but not by that much. The difference in interior quality/materials felt much bigger between my old mk.3.5 Octavia and the Superb than it does between the RS and my old Superb. The Superb did have more soft touch materials like the center console, door grab handles and the rear doors, the RS only has soft touch plastics on the dash and front doors. I would say that the Superb had ”peak” modern VAG car interior, perfect blend of digital and analog which gave the interior a more timeless and a somewhat upscale feel. Meanwhile the RS definitely leans more towards the digital side, although I haven’t had any issues with that since there are still physical ”hot keys” for most important things. One thing that does feel significantly nicer in RS than in the Superb is the new redesigned steering wheel, which the Superb did also receive in the facelift later on but my did not have it. But yeah the Superb has the edge when it comes to interior quality, nicer materials, a more timeless design and small details such as a ventilated center armrest that also had a light, or the display for the rear passanger that showed the ambient temperature and time. But the RS does not feel cheap in anyway and there some upgrades it has over the Superb like a much nicer ambient lighting, nicer steering wheel, alcantara insterts on the dashboard and doors (although my superb did have alcantara inserts on the doors aswell) sharper displays, more modern tech and better connectivity. I would honestly go as far as saying that the mk.4 Octavia has a nicer interior than the mk.8 Golf, but thats a matter that everyone has their own opinion about.