The cars with bigger gaps are going to be the closest to the original setup, as the cars did sit very high. There are 3 different types of spring pans with different heights and these can be used to change ride height (some cars even have different spring pans on different sides!). Personally I think these cars, even as road cars need to be lowered a little and as long as the spring rate is increased bottoming out shouldn’t be a massive issue.
If the gap is bigger, not only does it look wrong, it must affect the cars handling
You would think so but in fact the opposite is true as you lower the front of these cars the front roll centre is moved further under the ground, which has a negative impact on handling for a few reasons. The GTA’s had a ball joint riser that modified the front geometry to raise the roll centre when the cars had been lowered and vin sharp makes a similar item, this enables you to get the benefit of a lower CG without the roll centre issue. As far as the rear goes the opposite seems to be true, I run my track car as low as I can at the rear, problem with this, particularly with the 2L (Deeper Tank), is that the Fuel Tank starts to get pretty close to the ground.
But as far as mods go getting a new set of springs and setting up the ride height properly is pretty cheap and easy, so I wouldn’t base my decision on buying a car on the ride height.
cheers