Update on my use of the mod. Have done 2 100% races in career mode and I have noticed a few things. When you are in the pack its super fast when you are on your own its like normal career mode. If you are a rookie and/or don't play at full settings it might be wise to edit the difficulty other wise you will be battling for first while in a williams. However packs of drivers still form (sometimes a group of 2 and then a group of 5.) no matter what time of the race it is.
Really great mod, and from my testing the cars are not equal, which a great way to still have a good career type feel. I haven't gotten to test it in a race yett, but I'm going to be testing it on a 100% race.