tuning with supercharger

ECU doesn't need to be, "opened". The chip would go into the back. You'd see it if you're looking at the back of the ECU. If there isn't one then it was probably never tuned digitally.

You say there's an FMU. If it were tune for a blower with such tiny fuel injectors then it would likely have been done using the FMU. I can't recall a SINGLE instance where someone tuned with both an FMU and EEC.

What I mean is: If you're going to tune electronically, then why not get a fuel injector able to support the mods?

You're right though... it's just as likely he slapped the blower kit on and went down the road.

Lots of, "if".