odb1 vs odb2 is a myth started by one of the import car magazines.

They took two cars, one ODB1, the other ODB2 and installed the same header on both of them, then wrote a whole article about ODB2 being so restrictive when the header did better on the ODB1 car.

What they didn't mention is that every engine is different, and will respond to modifications differently. It would have been incredible if they *DID* get the same results. Going from ODB2 to ODB1 is reasonable if you want to install a chip, but for just the performance difference you are spending a ton of cash for nothing.