Clean racing is a thing of the past now, there is no such thing as clean racing unless you are in a private lobby with friends/club members these days.
Tbh no matter how clean you will race if you are good at drifting you can always get more points in the end as long as you combine it with other skills like sidesweeping objects.
The thing is that drifting and getting best lap times does not go well together. Personally i find the point system on the leaderboards strange as i always drive as fast and clean as possible but i know (as i tried before) that if i would just drift combine skill chains while not even finishing the race i would had gotten more points.
But oh well how i see it as long as you having fun by driving clean/less clean or drifing that is all what matters , the scoreboard is not really important and a bit tricky to balance perhaps