Advice on a 1982 KZ1000?

There's what looks like a good condition 1982 KZ1000J2 near me for $1600. I shouldn't be thinking about picking it up, but I am -- what are you gonna do? I don't know much about this model or the year for KZs. Does anyone have thoughts on this model? General value? Can anyone ID the 4-1 header? Thanks!

Anything with a J motor has crank problem possibilities. Take a #5 Allen wrench with you and pull the ignition cover off. Let the bike idle and give it little blips of throttle up to about 1500RPM. See how much the crank walks in and out. If it has visual walk, the thrust bearing is heading south.