On the ’80, toe is the only thing easily adjustable. It can be knocked out from wheeling, impact, so should be occasionally checked. For something that looks deceptively simple, vehicle handling is a complicated subject, there are great books on the subject, this will be the simple version: Toe-in enhances high speed straight-line stability. If set at zero the tires are free to move, play in the system isn’t taken up, steering feels light, prone to darting. With some toe-in, the tires are loaded slightly at odds with each other; this reduces the effect of play in the system, makes the steering feel more solid and reduces the darting effect of bumps. Overall, makes the rig more comfortable to drive. The stock spec is 0-.160”, I find that lifted, big tire rigs like a little more, at the top of spec. If the rig has been modified, it is often best to experiment with settings to find what works best. Like most other alignment settings, a lifted, big tire rig is likely to want different settings than a stock rig for best handling.