Sounds like he still has a lot of learning to do...
The CAI is a waste of money in a REX. The stock one works well.
The exhaust has to be selected based on requirements.
The ECUTek probably isn't turned properly. They MUST be turned to your mods and car. If he has detonation it's a clear sign it not tuned. It could have also blown the engine, which explains the loss of oil.
For performance, I'd take my rex over my focus anyday. Sadly, there's only so much you can do with a zetec.
The ugliness only adds to the charm!