This is very unpopular, especially coming from a Finn, but I think if Caterham was to change a driver next season, they should keep Petrov instead of Kovalainen. Of course, the best choice would be to keep both.
Caterham's treatment of Petrov is awful, they see him as nothing more than a source of money. Petrov seems to have absolutely no chance to retain his seat next season and according to some rumors is even going to lose his seat to Giedo van der Garde for the last few races this season.
![Surprised :o](./images/smilies/icon_e_surprised.gif)
He needs more sponsorship money to retain his seat, even though he is already paying for his drive, unlike Heikki. This while he is actually often beating Kovalainen in the races, for which he gets no attention unlike Heikki for qualifying better. In my opinion, Petrov brings more value for money and has less experience and thus more potential.
I also consider Caterham the worst team in F1. At least Marussia and HRT have their smaller budgets as an excuse for their lack of performance. And they haven't constantly made false promises to their drivers and fans about improving their performance.