first, if you and your family aren't used to play racing games their eyes aren't used to "imagine" the distances, so usually ppl enter at too fast speeds for that turn, second the turns look less tight then they are, for example the turn after the big straight (not the finish straight) looks like a turn that in real life I do it at 160 km/h with my car (you're not a cop are u? :P) but after test the turn I can only do it at 120 top with a similar car, third: the "normal" tires setups are made for racing which have temperature changing much bigger than real life... in real life even with cold tires or real hot tires they have a almost similar grip, in the game no, so if you have cold tires ouch.
so until you practise a bit... try other games also to compare... you'll find it quite "unreal"
for me only lfs and richard burns rally are good simulations, (ok gpl also but not my thing)
try gtr2 or rfactor, they simulate racing quite well, but they dont simulate out of the expected... so for example even if you put normal racing tires instead of slicks, it still is impossible to do correct drifting.
dont forget in the demo the 3 cars you have are like old cars... no good downforce, no esp, no abs, so they are harder then most cars that you can buy now. if you could try a fz50 with traction control you'll see it's easier, even without it it still much better then those 3.
for me only rac is a but unreal... in real life that car would cause too many accidents... I bet that in real life that car has more tendency to understeer than oversteer.
and the formula 1 car wow...
that shows how important downforce and good grip really are
sorry for big post, but hope that helps a bit