Personally, I like the new sounds better for the most part. I think they are lacking at the top end on most cars, but there is only so much you can do with speakers and sound generation.
I do have one comment, and maybe it was said before, but I just wanted to comment.
I think the biggest difference (other than the basic tones) between what we hear in the game and what we hear in the car is the environment.
The way I look at it, the sounds we hear are as if you were driving down the road and there was nothing there but the engine, or nothing there but the transmission, or the exhaust. You then take all those sounds and pipe them to your ears at the same time. You end up with a decent mix, but you are still hearing individual sounds.
In a real car of any type, the whole car, and especially the cabin on a tin top, act like a resonance chamber. Yes, the different structures within the car will muffle sounds, but they will also transmit vibrations throughout the car and what we end up hearing is different from what was originally produced. We end up hearing different sounds, but we also hear mixed sounds and tones that can't really be traced back to just one source. Just try to isolate a noise in your own car some time. What is generating that sound? It is very hard to tell sometimes, especially when you have a squeak or rattle or clunk. You might be able to tell it is coming from the back of the car, but maybe not. It is like a giant mixing chamber that alters sounds enough as to make it more of a symphony than a group of single instruments.
Put the exact same engine, exhaust, transmission, differential, wheels, tires and the same level of sound proofing into two different cars, lets say a XRG and XFG (in the real world) and the cars will sound different while you are in the car. The engine might sound exactly the same as a single component, but the end result in the car will be different.
I think that the team is on the right track for the sounds. More work will be done in the future. What we hear now is great, it is so much more communicative than other sims. It will get better and better as we move forward.