i'm going to modify my throttle body, and i'm looking into modifying the maf too.
3" mafs from the 300zx will fit, as they use the same sensors as us. Â however, they are close to $400 2nd hand. turbosmart make 3" mafs, you could possibly suss out their range of goodies.
otherwise, i believe you can get the maf machined to around 54mm (from 50mm)
i know someone that can do these mods (oversizing of stock components) after i had mine successfully done, i was going to offer a changeover service if anyone else was interested.
i believe shaunk was talking to me about getting these mods done to his ca20e pintara too..