where it's labeled as 3071. My best guess is that the compressor sides of both turbo's are the same? or perhaps it was labled erroneously, I've never heard of a 3031, only 3071 and 3076. I've also seen the map for a 3071 from different site's and it looks to be the same map, only on this one sparkie has done the work of plugging in numbers for the vg30, so that's why I chose to use that.