In most cases it's not straight forward. I installed an '88 Prelude drivers seat in my '89. It's nice that the seat is fully adjustable for sides, back, headrest, fine adjustment for the reclining, and a memory setting for the major recline.

First I swapped parts on the inner rail. I used the CRX bottom that attaches to the body and Prelude top that attaches to the seat. The slider was really tight so I shaved some of the plastic off the bottom guide to get it to go together. This will allow the seat to bolt into the car at the proper height and centered. The one thing that really sucks is getting the rails apart to swap them out.

The outer rail took a little more skill. I wanted to re-use the OEM mounting points instead of drilling holes in the body to try and bolt the seat down. I got the seat in place and bolted down at the inner rail, then made sure both rails were adjusted evenly with each other. Then I checked how far off the Prelude mounting holes on the outer rail were from the holes on the body. Then I fabricated some tabs and welded them onto the Prelude rail.

Everything bolts up straight, the seat is awesome comfy, and the finished look appears stock. The adjustment knob on the right side barely clears the Integra armrest console I custom installed(something I thought would become an issue in the middle of the project). In the end I'm super happy with the results. I'll see if I can't get a couple pics up sometime.