the autocross pretty hard, so I need a versatile seat. I like the stock seat but they are heavy and in my opinion don't support my head the way I would like. I was considering a 1 piece for 2 reasons. (1) Lighten weight, which is what I am supremely shooting for in my Z (so far shaved a lot of weight). I wanted something that was light weight yet comfortable, I could live with 20lbs but not much more. (2) I figure they would work out very nicely on the autocross runs for snugness. But, again I don't know as I haven't sat in a whole bunch or performance seat.