I don't know if it's 67mph lol that was a mild guess... 50mph is the best in 6th as most of my trips are single carriage way I get it alot.
I've got well into the 40's with mine on long trips, it's all about patience and music... I don't need to go fast whilst music is on unless someone pisses me off or I am in Cupra R need the toilet mode haha
I didn't think the gear ratio went that low in 6th. I'm starting to think there's nothing wrong with my car after all!