Sorry to post here but you didn't have a GtVault email listed, and to reply over PSN would have taken somewhere close to forever.
Is it possible to gold the S.Vettel on a DS3?
People have, so yeah it is.
I was determined form day 1, when I first realised that the S.Vettel challenge was so difficult, that I would get it done on a DS3.
However I found it very difficult, I was able to gold Monza on a DS3, and was able to get bronze at Suzuka and the Nurburgring, (2:14.771 [2:10.000] Suzuka, 2:10.627 [2:08.000] Nurburgring). The simple fact is you just don't get enough steering lock on the car, and the wheel transition is just too slow, and when you go to a wheel you should find that driving the car is so much easier, even if you are no faster. I was struggling to carry enough speed through some corners while for chicanes you constantly make it through the first corner and just keep going into the gravel.
I put in abut 3-5 hours at both suzuka and nurb both before and after the controller sensitivity patch trying to crack this, the patch made it possible to advance much farther while before it was a struggle for bronze.
The main problem is that its very hard to finish good laps on the controller, so you get disqualified all the time making it hard to learn the car and track and experiment with lines to try and eek out those last few tenths.
Once I went to the wheel I improved my times greatly for the same time I put in (I did my wheel runs way later and far apart) and got to 2:08.990 [2:08.000] after 4 hours at the Nurb and 2:10.962 [2:10.000] after 3 hours at Suzuka. My problem was I wasn't used to the wheel, so a lot of my time was getting my head around it, and then the car again. I finally golded Suzuka 4 months after my first wheel run, it took me 5 hours to do it, and I was just failing to string the laps together for the last 1:30 of it, as I was just tired from racing and it was 2am. But after I got gold in Suzuka I went to the nurb 2 days later, and it only took me 45 minutes to get gold there.
So in summary, if you really go after it for a few days, you may well be capable of getting gold in all 3, certainly you'll get 2 silvers and a gold, but I found that I had to go to a wheel to make any real gains, for which my DFGT wheel, in which I unplugged the force feedback did the trick. (The FFB in the X2010 is really weird, where it goes light when you turn, making you think it is oversteer, so I just got rid of it for consistency.)
You can't really lose out from learning it with a controller, as you get a good base level of what kind of speed you need to carry and how the car reacts.
I hope this helps
Oh yeah, ages ago after I got so close on my first wheel runs I found this guide on GT Planet, it didn't take long to realise that it is impossible to replicate what he did on a controller, and trying to copy didn't help much either, but it showed me where I could try and go faster than I had before, (turn 1, degner 1 and spoon curve for example) as a weird thing about the X2010 is tat you can be 50km/h slower than someone else and think you are on the limit. http://www.gtplanet.net/forum/showthread.php?t=154480