I will not be making a habit of it, just wanted to test it after mcjihge2 mentioned it, wanted to see how beneficial it could be and while I had a few bits to do this afternoon I thought I may as well try it. I'm very surprised how well the assists can drive you round the track as well, it's a very dull way to level up though. The levelling system 100% needs some tweaks, no one is going to have the motivation and/or time after loads of hours in the game to constantly be driving cars for 3-4 hours so they can get all the upgrades on it.
I meant 25 car levels too btw
Edit, just tried driving the BMW without any assists (barring ABS) on the pad, stock settings for the pad are very twitchy aren't they?