map sensor cheating?

[banpei]

The issue is that the vacuum on the MAP system is very different from the vacuum on ITBs. For the MAP system, there is a single sensor, as it's a single throttle body. By T-ing the four vacuum lines on the manifold, you will get a very different vacuum than on the single throttle body. This is apparent in both low-end and top-end. Usually, this isn't a huge issue to remap with an aftermarket ECU, but on a stock ECU this is a problem. Some people (like Robokill) use a stock ECU with a different map (e.g. using a custom EPROM), but this is not something you can obtain freely.

About the 02 sensor: some European ECUs did get a cat, so they also have an O2 sensor. However, if your ECU doesn't have a cat, it will not do anything with the O2 signal.

Edit: You could try to go for a Speeduino (which is not a piggyback), but keep in mind that you would have to create your own tune that matches your ITB setup. Even if there is a 4AGE map available for the Speeduino, it probably would be different from your setup, as it could differ in manifold or ITBs used. Most of the cost for aftermarket ECUs isn't in the ECU itself, but in creating the right map.