You should rent it CHuff and give it a go. ALl the developement stuff is just beating set lap time sin practice to unlock the developement bits. Theres also quick setups which is what I use as I can't be bothered spending ages tweaking the car.
This games works on so many levels. You can go all anal and do full length race weekends and fine tune eveything or just do short races with every decided for you and hammer round the track.
Nick