The cobra one actually requires a $125 "harness adaptor" from JWT to read over like 375hp or somthing, where as the Z32 one will do 550 before it's maxed out. The only reason JWT uses the cobra one is because if you go to the dealership they are cheeper than the Z32. I got my Z32 out of the scrap yard for $75 and that included the harness, and the 2 K&N's the car had on it. Sold the filters for $35 so the thing ended up costing me $40 out of pocket
Just start going to the scrap yards and looking around, the NA and TT use the same MAF, so that makes looking a bit easier.
later,
Paul