Well, if you're putting in racing seats, you need the harness and harness bar, they're a system. Can't have one without the others, I learned this the hard way via an accident two months ago. I didn't heed the advice the senior track members on here gave me and now I'm at the chiropractor 3x a week. I had the 4pt harness with no harness bar and stock seats. I was rear ended and it compacted my spine, just like I was told would happen. Had I listened, I would've smacked my face on the wheel (ouch), but I would've been fine the next day. Instead, my spine is now messed up, possibly forever. With that said, think about getting the whole system installed together. Your spine will thank you. The seats are a little different, but what will your next toy be? Lemme guess, racing harnesses?...........