They sound fine to me in GT5, just need to turn the music down a little. Especially my Camaro with the full racing exhaust installed. It put the pipes out the side, sounds pretty wicked.
I forgot that I took a quick picture of my Driving Force GT. I now realize it doesn't show the stand I bought :( and its fuzzy since the HDR was on and it wasn't completely stable as I was driving.
I'll try to get a better one tonight.