I find GT3 to be more realistic. GT4 is fun and is a VERRRRY good racing game, but not such a great drifting game. It's a fun game to drift due to the difficulty, but I find it unrealistic in several ways, and don't get me wrong I'm increadibly talented at GT4 drifting, and real life drifting in my 300zx. Yeah, I've gotten lots of tickets due to that. Police call drifting "exibition driving" by the way.
With practice, I've always been able to drift every track on GT3 either as show drifting or speed drifting, or street drifting on street courses 'cause they are a comb. of the two. While show drifting I can link from start line to finish line on most tracks w/o ever losing my drift. Yes, even Complex String. Of course sometimes it will take up to 48hrs. per track to get this just right. Or I could low angle speed drift and not drift the straightaways to drop my drift lap times. So yes, GT3 is easier to drift, but not much.
In real life street tires are very forgiving and racing slicks tend to be very all or nothing like. Unfortunately in GT4 all tires handle like racing slick tire physics, just some with less grip than others. If you ask me Enthusia Professional Racing has most realistic physics you will ever find. I think they should have left the GT3 physics engine alone and just tightened them up a little bit with the racing tires and only those tires, in real life they drive different than treaded street tires. GT4 has good race tire physics. GT3 has good street tire physics. Also in real life that "snap overcorrection" problem is none existant, with street tires, that is, happens all the time to cars with racing slicks (that's why I think what I do about GT4's physics engine). In my real car I have never done more than straighten out and be on the wrong line from an overcorrection before.
I personally love GT4's drift physics for being so hard however, because it's so much fun.
