Yeah the online functions are not very good.
I dont think you should care so much about online lap times, since there is also a lot of rubberband effect in the race games. You can not be sure, you or your oponents cars are driving in under the same conditions even if both use the same settings.
There is also another easy way to get online wins. That is to play time attack mode, with stock cars. Just let them get a litle ahead of you, and then when the road is clear, set a good lap.
Seems to be rather easy to get online wins using this method, even when driving on pro settings, most of the crashers cant beat your time even, if they use easy / assisted settings.