I can enjoy a good arcade racer (I've played through NFS:MW) , but lately I've been focused on simulation racing.  Over the last week I've been putting quite a bit of time in with Forza 2.  I do enjoy Forza 2's framerates (rock soild at 60fps -- makes NFS:MW look and feel so slow), and I really appreciate the physics 'framerate' at 360/second.  Updates that often are very important when you consider that a race car will easily have moved 2 feet in 1/60th of a second, and throughout that movement you will have no incremental calculations if you only do your physics work once per frame.  Two feet is a ton of distance when you consider that you routinely come inches from going off track or hitting a wall if you're racing hard.  It's nice to be able to dedicate an extra processor core to doing nothing but physics calculations constantly.

I also realized that realistic damage modeling is critical to racing sims.  I originally set damage modeling to 'simulation' so I could get additional credits for completing races.  In Forza 2, you win cars regularly -- just about one car is won for every single cup -- plus you get bonus credits as well as credits at the end of each race for your performance, difficulty, and car rarity.  Typically, you use these credits to upgrade parts and tune your car. 

The more I played the more I realized that my racing style changed completely because of the damage modeling.  I played a lot more realistically -- avoiding any major contact with walls and competitors as if my car depended on it.  It's not like I avoided touching other cars and racing aggressively altogether.  I just played as if I was actually racing a car, not as if I was playing a racing video game.

Not only did the racing become more interesting to me, but because I had to race more carefully I spent a lot more time upgrading and tuning my cars and enjoyed that aspect much more than I had before.  You quickly end up with well over a dozen cars in Forza 2, and you need them at various performance levels for various races.  Like similar racing games, you can only enter certain cars in certain cups.  Perhaps you have to race a European car, or perhaps a midengine car.  Or perhaps you have to have a car with fewer than 400 horsepower or that weighs less than 1800 pounds.

During races and replays, you can check the telemetry at any given moment. For example, say you were pulling through a turn and you accelerated a little too quickly, spinning out.  You can view the replay and check to see how much friction from your tires was being spent on centrifugal force and how much was being spent on acceleration -- that might give you an idea of how hard you can accelerate coming out of corners.

Overall I have to admit that Forza 2 is easily the best racing sim I've ever played.  Graphically, it didn't blow me away, but it looked good and the far more important aspects include the 60fps solid framerate, the 360 physics updates per second, and the realistic damage modeling.  I'm looking forward to its sequel.

Agreed, Forza 2 is the best racing game I've ever played. While the damage model isn't 100% realistic, it's realistic enough to keep you on your toes. I really like how things like drafting and (especially) turning play such a major role in the game. It's amazing how much those 2 aspects are neglected by most people online, there's an art form to it that in the course of 5 laps can mean 10+ seconds especially for the American RWD cars.

I can't wait to see what the next generation of racing sims are like, that's when it will start getting really, really interesting.

I wonder if Gran Turismo 5 will have damage modeling. Originally, the guy from PD said that they were considering it, but that it would add considerable length to the development time, as they would have to render each damaged panel of the car separately, and it was already taking a single programmer 180 days to model one undamaged car.

However, just a month after this Kotaku reported that the game would definitely have damage modeling. So far, they're the only website to have reported this, and it would totally suck if something got mixed up in translation, and the game wasn't really going to have damage.

Of course, PD has said that they could add damage in via updates, and there has been speculation that they'll do this for GT5: Prologue, and that GT5 in it's finished form will come with damage.

Forza 2 is very far ahead in terms of realism. It'll take alot more to get GT5 as good. I played the demo of GT5 with my mate. It's not very realistic in comparison.

well,

I dont believe that the modelisation of the dammage is important
it is better, but not so critical
but
I think the modelisation of THE EFFECT of the dammage is important
the fact that ur car suffer when u make some dammage is the key point to make people drive more carefully like in the reallity.

for GT5 I dont believe that the dammage will be present...
I dont know why but I bet more on "weather" adddition, but not dammage.

once i also used to only like arcade racers but after playing GT3,4 and forza2 and like sim racers more now

Yeah. top game... i also like GT, but not as much as forza

I've played quite a bit of GT.  I kept playing it because I felt like I should, but it didn't seem nearly as much of a simulation.  It's hard to drive the cars, but I didn't get the sense that they were really behaving realistically.  With Forza 2, you can see how the forces are working on sections of your tires, for example, and you can see why and how things happen.  The rules Forza 2 contains are a simplified version of reality, but they seem much more complete than those in GT.  

And the level of customization that you can do in Forza 2 --  both in terms of tuning and otherwise -- is awesome.

If you love cars, it just seems like Forza is easily the better game.

I hated how one of the most realistic racing sims just kept giving away cars everytime you won a race. I ended up with 12 cars within an hour.

It felt so unsastisfiing to win cars, which was the total opposite in GT, winning a car or getting enough money to buy something in a new category was thrilling. Forza's prize system just ruined it for me....

So I gave my copy to my brother within a week and never played again.

GT4 has exactly the same system. Ya win a series get a car. Forza 2 has eliminated part of the problem by making the cars you win worthless if you sell them back to the computer.  At least Forza 2 lets you RACE and Upgrade the cars you won (I'm looking at you Diamler Motor Carrage & Jay Lenno Tank Car).

Forza 2's only weekness for me, is endurance races are too damn short.  The longest endurance race is less than half the legnth of the shortest GT endurance race.  Even some of the series races are longer.