I remember an interview where Pat Symonds said that the 2012/13 cars have much more downforce than those in 2003. And he was talking about the Marussia. Don't know where that was, maybe i'll find it.
Found it, was a two-part interview over at AMuS. Couldn't find an official translation so Google Translate might have to be your friend this time:
The relevant part:
AMuS: With your people and your budget, where would this Marussia have been in 2003, 1993 and 1983?
Symonds: We would've won everything. Even 2003. Of course, in 2003, there were much more powerful engines than today and different tyres. We'd have to account for that. But i know the differences in the downforce levels. Our Marussia has much more downforce than the 2003 Renault, even though the regulations have changed to the disadvantage of aerodynamics. Concerning downforce, the top cars today are far ahead of the 2008 cars. Back then, aero regulations were much more open. In 2009 alone, regulation changes cost us 50 points of downforce. In 1983, you would've been said to have magic powers if you had built a Marussia.