I replaced the original track bar on mine with a NAPA unit in mid June. In about a month it was sloppy and ready for a replacement. Yes, they have a life time warranty and yes, they gave me a new one. It's been a couple of weeks and so far, so good. If this one fails I'm going after my money. I still have the original bar and will do the Lukes Link on it and say nuts to NAPA.
And yes, they source the track bars from various suppliers. Both of mine had different brands on the box and the counter guy said as much.
But no, I don't believe you have to realign the front end. All the track bar does is keep the front axel and attached parts from shifting left or right. It does not change castor, camber, height, length, grow hair, reduce weight, or whiten your teeth! Just makes the truck drive straight when the driver is.
JK