The K-series is going mainstream. Plenty of shops are getting experience doing the work, plus there are finally enough wrecked RSX-S engines in the junk yards that prices have come down a bit. There's also been enough time for companies like Karcepts, Hybrid Performance, and others to build entire parts catalogs around the swap.
If you're planning a K swap or if you have one and want it as complete as Honda would have done it, then read on-getting power steering to work with your K swap is a little more complicated than it looks.
It's easiest to break this down by chassis. First would be the '92-'95 Civic and '94-'01 Integra. These are pretty simple and straightforward. Obviously a chassis like a Civic CX that never came with power steering works well without it, but if you wanted to add it, the easiest thing to do would be to add an entire subframe with the power steering rack in place of your non-PS unit, as it will bolt right in.
For those of you with a power steering Civic or a Del Sol, you may want the Integra unit, as some of the Civics and (near as I can find) all of the Del Sols have two returns, but the Integra has only one in and one out. Even better, all Integras share the same part number for the steering rack, which means one is not better than the other. Be sure to get the Integra coupler (from the steering shaft to the steering rack) as well, since the Civic's is too small for the Integra rack.
The easiest way to start this...
The easiest way to start this process is to get a 94-01 Integra rack and subframe. Most '96-'00 swaps use them and they bolt right into all '92-'95's. The EH is on top and the DC is on the bottom in this photo. The DC has only one in and out, and has a faster ratio than the EH; definitely worth $200.
From here there are two routes. First is to use the power steering pump that came with your K-series. In an EH, the problem is that the pulley won't clear the hood. The solution comes from Jackson Racing in the form of a smaller pulley. Go here: supercharger.com/shop/OrderByPart.aspx-the part number you want is 052-154. The smaller pulley is $92 and bolts right into place.
Next you need a belt-52 inches for K20A/Z1 crank pulley or 52.2 for K20A2 crank pulley. Other crank pulleys, like K24, are typically larger, so a longer belt will be needed. Next is the high pressure hose. Amazingly enough, the one from an '02-'04 RSX (any) is a perfect match-no modifications are needed. For the pump's return, you can do it a number of different ways. The same '02-'04 RSX has a workable reservoir. Same for the Integra, or, if keep your EG steering rack, use an EG reservoir because it has three inputs. You may need to do some cutting or use custom hose, though.
Finally, install some sort of cooler. Power steering fluid runs at incredibly high pressure, as high as 2,500 psi. And it's not helping things by installing a smaller pulley, which is making the pump turn faster all the time. Perma-Cool makes a generic cooler, part number 1007, that is less than $50 and works perfect. Run the return line from the rack and then out of it to the reservoir.
With it all installed, it's likely you'll need to clear some of the underside skeleton of the hood, but that should be all. The only other thing to look out for is the return from the pump to the reservoir. It generally sticks up just enough to rub the hood, so some extra clearance or turning it upside down may be needed. For everyone with an Integra, the hood doesn't slope as steeply, so it's not as big of an issue.
The EK or '96-'00 Civic is of course different. This is mostly because of the various companies that make the mount kits, and how they position the engine. But like the EG, the easiest thing to do here is swap in the Integra subframe with power steering rack since it bolts right up (you can't do this with the Hasport EKK1 kit). There is just a bit more hood clearance on the EK, so things won't be as tight.
 When you get the rack, be...  When you get the rack, be sure to get the splined connector from the DC rack since it's a larger diameter on the rack (versus an EG), but the same on steering shaft. |  The stock K-series has a huge...  The stock K-series has a huge pulley on it. So big it would go right through the hood. But for $92, Jackson Racing makes a smaller pulley that bolts right up. |  Now you need a high pressure...  Now you need a high pressure line. Lucky enough, the '02-'04 RSX (any model) is a perfect fit. Direct connection on both ends. |