Is the Kohler Highline a good toilet for a main bathroom?

Yes for a standard-height setup. It flushes reliably and parts are easy to find. If you want a taller bowl or a one-piece design, look at comfort-height or one-piece Kohler models instead.

Does it come with a seat?

Yes, a seat is included. Many owners replace it with a sturdier seat, so budget for that if seat quality matters to you.

What rough-in does it need?

It uses a 12-inch rough-in, the most common spacing. Measure from the finished wall to the center of the floor drain before buying.

How much water does it use per flush?

1.28 gallons, which meets current federal efficiency standards. That is the same as most modern two-piece toilets and less than older 1.6-gallon models.

Is it comfort height?

No. It is a standard-height bowl, roughly 15 inches to the rim without the seat. Comfort-height models sit about 2 inches taller.

Is it hard to install?

It is a standard two-piece installation: set the bowl on the flange, tighten the tank bolts and connect the supply. Most DIYers can do it in an afternoon.