It's nice to see these comparisons. As I said in the past, GT4 kind of went old school in track design from past tracks. Classic tracks redone in Gran Turismo 4 look more realistic than GT3. It's almost as if you could watch the race on TV from Speed Channel (that is, unless some oval race hasn't been delayed for rain or a serious crash), Ten Network (Australian V8 Supercars), SkySports, or whatever is your favorite or only motorsports channel.
Midfield Raceway (first comparison) looks more like this fantasy track actually exists. Or who knows? You might see Tiff Needell and Vicki Butler-Henderson do some insane driving or road testing at Midfield. Looks pretty real. Next is Laguna Seca. Even though I tried it once, who the hell would race Laguna Seca backwards? Anyway, I think GT3's variant wanted to have something different, an evening event at perhaps America's toughest road course. Some have their say about it, but I kind of like GT4's rendition with the green grass. Of course, if PD wanted to include the Bahrain F1 track, I'm sure they'd include all the white sands and not patch things up with green grass. By the way, I loved the coverage of that FIA GT All-Star race in Bahrain. You guys rock! Grand Valley Speedway is the next course. GV in GT4 again looks more realistic, and with the old-school style, you'll be seeing a bit of the city as you head into the turns. I don't like it. I love it. Swiss Alps is the last comparison. It's a bit of a toss-up, but for the extra mountain detail, Swiss Alps in GT4 is better. Never heard a lot of respect or disrespect for Swiss Alps, but the jumps are cool.
So all in all, I can dig the new styling touches on some of the older tracks. Nice comparison. Since I'm a city guy, would like a Tokyo R246 and Special Stage Route 5 or 11 (whatever is in the game) comparison.