I lose 0.3 seconds on average in each corner. It's very easy to calculate my theoretical optimal laptime from this. On most tracks it's usually between 2-3 seconds. On longer tracks, you multiply by the number of corners accordingly. Sarthe I lose about 4 seconds and Nurb 24 I lose about 13 seconds. I never drove to a time, but this gap has held true for all cars/tracks combinations so far. In Daily A races with slow cars and short tracks sometimes if I push more I can get it slightly lower, but as someone has said who knows how fast the top aliens are pushing on the leaderboard. I think it works out to be the same in race situation though. Even aliens won't do their perfect laptime every lap in the race, and slipstreaming also gets you a few tenths easy depending on the track.