I haven't seen this mentioned, but undeniably the worse thing about gran turismo 3 is that it doesn't show damage. Im not talking about hitting the wall damage, but normal wear and tear, such as breaking the steering column, bending a tire, loosing a gearbox, malfunction, anything.
Also, in my experience with actual racing, body roll is the most poorly portrayed thing in gt3 I have ever seen. This is where actual driving comes into play, managing to shift the cars weight to the appropriate place for correct turning grip, without spinning, bottoming out, slowing the car down excessively, breaking something, et cetera.
Oftentimes in real racing, the drives loose gears, or have mechanical malfunctions, and they have to adapt immediately to continue racing and stay alive in the points championship, and manufactures championship. This is why they are the best.
Also, in my opinion, oval track racing is portrayed poorly in Gt3, the physics, and settings for camber and toe are completely unrealistic, it is as if they don't take into account the spring rates, im running a mixture of kart theories which run without springs, coinciding with damper rebounds and bounds from real racing, to get a correctly handeling vehicle. Now you tell me how that is realistic?
Also, in gran turismo, you have no idea of the heat, forces, strain, et cetera that real drivers go through.
I'd also like to put this in :
I drive a 1994 firebird coupe, with a very low 160hp, and 200 ft lbs of torque in a 3400 lb car. I have been racing karts for 4 years, this is at the level of professional mind you, and have done every racing sin game I know.
After I got my license and have had them for about a month, I decided I knew everything and began to over accelerate my car. Now it isn't even positive traction, but I nearly got myself killed, when I took off to fast from an intersection, and the rear end broke loose halfway through the left handed turn and it continued to fishtail for the remainder of the turn, with me almost hitting a minivan RUNNING a red light.
Given, I feel my experience in karts helped me quickly straighten the car back up, and I could feel when to brake/accelerate/degree of turn et cetera to regain control ASAP, however, none of this is experienced in gt3, and neither karting nor GT3 helped me keep this from happening.
I guess the bottom line is that real experience in an actual racing machine is the best form of training ever, but there is a reason that none of us here will make it to F1 racing, nascar, trans am, rally, et cetera.
Because we are not the drivers, they are.
-Sominon