Whilst I agree that it would be nice to see a "filter by input device" tab, I doubt it'll ever be implemented. I'm a DS3 user too, but really don't mind that people with far more effective input devices beat me in the trials etc.
I'm more into racing online with friends, most of which have wheels kits etc, and yet I can still stay with them. With the right car setups I can even beat them, mostly thanks to consist laps and knowing exactly how the car will react to a given corner, bend or bump.
An example, we ran a GT500 race on Tokyo R246 over 15 laps using any GT500 car we had. A couple of the regulars brought out the usual GTR's and Supra's, whereas I used my Mobil1 NSX. With the DS3 I was a clear 3 seconds per lap faster than everybody else on circuit.
The key thing is to learn how your car will behave and then practice, practice, practice. A good setup will get you far, confidence in that setup will get you further!