It's becoming clear that the best place to practice for online events is your own lobby rather than the offline 'free run' mode. This is because of the physics changes caused by tyre temperature and tyre wear, which can have a huge affect on the way your car handles. However, there seem to be even more reasons to use your lobby than first thought... it may even render the offline 'free run' obsolete. I've been driving a brand new car in my lobby all evening, and must have put in at least a couple of hundred miles by now. I went into my garage to check... 0 miles. Yep, any mileage you do in online free run does not get added to the car, nor does it get added to your profile total. But there's more. On removing the few upgrades I had applied, I found that the cars BHP was exactly the same as when I started. In other words, there was no 'engine run-in' affect. All that being the case, I would hazard a guess that engine wear, chassis rigidity, and oil cleanliness are all disabled during online free run. Add to that the fact that you can take multiple cars to your lobby and switch at will with no loading screens, and it makes it the best and most 'economical' place to practice with your cars.