I know what the difference is between the 2... the 5-pt has an extra strap that goes between the legs.
the question is: is it worthed ??
does it really make a difference ??
I'm getting seats and need to know if I get the extra hole in the seat or not.

Thanks,

This is something I actually have some experience with. Albeit not a great deal.

I prefer the 5 point, particularly when braking hard. Overall, I felt much more secured. Most of that was probably psychological

For real track use, I'd do 5. For a street "toy" run amok, I'd think 4 would be ok. The problem with 4 is that pulling the shoulder straps tight will pull the lap belt up. This can cause injury to internal organs in a crash....not good. I'd go 5 points if it were me.

Some clubs by me won't allow people to run with 4-points. They would rather a stock seat belt than a 4-point. I'd run a 5-point if I were you. They actually make 7-points now. They talked a bit about them when I was at WGI.

I'd suggest the 5 point also. You can cinch everything down much tighter without raising the lap belt up. For autocross i like my belts real tight to the point where I can't move even if I try.