The trainer does not really gives me a plenty money. I can buy new cars, yes, but no paintings, turbos and other stuff. The amount of money is negative after I have used the trainer
I'm having the same problem as Alpollo. I even tried the steps that CyPHeR369 outlined and the issue persists. I'm guessing the trainer just needs to be fixed/updated.
I've tried editing the money value on my own with CoSMOS, but it was a no-go. (It's easy to find your money, but for some strange reason, it doesn't actually change.)