What do I need and How do I install racing seats into my 93 integra?
You’ll need the seats, and you’ll need to have the brackets that are already on your car modified so that the holes at the bottom of the racing seats can be bolted onto the brackets. The easier way is to just go out and buy the brackets off of ebay that are made for our cars. They are usually fairly expensive, and may not be a perfet fit or anything, but they will be pretty damn close and they are a VERY easy installation. It’s basically just bolt the seats onto the brackets, then bolt the brackets into the floor of the car… all the holes will line up, it’s very easy… but in many cases you can’t slide the seats 
In my opinion, custom job = better. Bring it to a respectable shop and get them to weld your existing brackets to fit your seats. You’ll be happier with that in the end.
When I was getting my racing seats I checked a shop and they were going to charge $150 to modify my stock brackets to work with my racing seats. I ended up getting a set of Weapon R brackets off of eBay for like $90 and they work great, the seats actually can slide forward and back farther than the stock ones and the brackets even have a place to mount the stock automatic seat belts.
i did the same gekko did. i bought my weapon r brackets from ebay for 90 shipped. however the sliders didnt align with the bracket so i had to custom drill new holes. also i had to bring my brackets to a muffler shop and have them weld on a new metal bar so it will fit my seats.
I just modified my stock brackets. You’ll need a welder thats for sure.