Single seater and tin top racing are very different to each other; and the driving and racing styles are very different.
I’m aware of that. It didn’t stop Paul di Resta, though. He won the 2006 F3 Euroseries, then did four years in DTM and joined Force India.
Then you’ve got Robert Wickens, who started out in open-wheelers and won Formula Renault 3.5 and came second in GP3 and Formula Two (and third in Champ Car Atlantic – he’s had success in practically every category he’s raced in), before joining Mercedes’ DTM effort.
Likewise Roberto Merhi, who won the F3 Euroseries last year, and had a few podiums in GP3.
I think that with Paul di Resta, Mercedes have proven that a driver can successfully move from touring cars to Formula 1, and that they are now accelerating their driver development programmes to get the likes of Wickens and Merhi into the sport.