Live4Speed, cars come with differential gears, that also can change how much or little wheelspin there is. Remember GT is working with fixed number values for temperatures, tires and road surface. Turn on tire damage and see if you can spin wheels more, i think you can. GT4's fixed temps cause the tires to spin down till the grip, which is stupid, that never happens in real life, but if you are burning out, you'll never grip unless you throttle back anyway.
About that TCS and ASM being off, i think that just about every car from the late 90's comes with ABS, ASM standard, TCS is think isn't a normal thing, since most road cars don't have the hp to break it's tires free under acceleration. I think car from MB, BMW and high class GM and Ford cars come with TCS. That should clear up having them off by default, if they are equipped on the vehicle IRL, then they are on by default. In the game there should be some sort of hardcore sim mode, which leaves cars in their real life states, exactly as they were on the showroom floor. This game comes with man handicaps set up for those who are new to the game, reason being, not everyone will want to play GT if when you first play you can't accelerate correctly, or maintain control of your vehicle. The game caters to casuals and enthusiasts alike, line had to drawn somewhere. Hopefully the next installment comes with no training wheels for the fardcore, and a handicapped mode for the uninitiated.