Tom nailed it. It's not just the length of the MAF tube, but how straight the air is before and after. A BOV too close will also mess up readings.
'04 Mach 1. Built. Turbo. 667whp/631wtq
'06 Focus. Built. Turbo. WMI. (sold)
'03 Mach 1 : 12.61 @ 106.59 (sold)