1 - the difference in suspension can change the way a car accelerates, launches and how it reacts to forces applied
2 - the shortest way to explain this follows:
a wheel with 0 toe's face will be perpendicular to the body's angle. changing this angle will alter the amount of grip and spin a wheel has. normally the higher the toe the more restricted a wheel is and normally less spin. but even with less spin there can be too much restriction which can be a deficit to times.