Thanks for the explination, Dave. I asked partially for myself but also partially for anyone else who is wondering.
As for the money issue, it's not a real concern in terms of NRS. I shouldn't have even mentioned it. But let me explain something...
Maybe I'm a super-nerd about this, but I kind of treat my GT Mode game like an RPG. I make up goals such as buying a particular car or making a certain amount of money and then decide on how I'm going to do it. I try not to repeat races just for the sake of making money, so I usually pick a new series that I haven't done yet and build an appropriate car to give me a decent chance at winning.
I set up my car such that I might have a slim chance of winning but expect to get 4th or 5th place. After losing the first time through, I either change cars and try again or head to the tune shop for upgrades. It can take quite a while but this is how I like to play.
So, just getting the car for NRS is part of the game, for me.