here the response to an e-mail that I sent to Idmar......
"I am happy to hear you love your Hammerhead ... it is my favorite
engine of all the engines we build.
It would be pretty impractical to convert your engine to the ETX CAT
system. Of course the manifolds and exhaust outlets would have to
change but you would also have to change the engine wiring harness and
the computer that runs the engine. There are also some additional
sensors and some other components that would need to be added to the
engine. Another major problem would be that the 2008 vintage computer
that runs the engine is not compatible with the 2007 computer in your
boat that runs the dashboard etc. By the time you would get it all to
work you would have a significant amount of time and money invested
that I am not sure would be worth the
> I have a 2007 Malibu VLX with the HammerHead engine.
> First off, I would like to thank You guys....I love the engine!
> However, the Etx-Cat system was not available on the HammerHead when I bought mine.
> Is it possible to add it on now?
> I am pretty handy with a wrench, or my dealer at Waterski America
> would be glad to help.
> Is it just a matter of changing manifolds, or is the engine brain
> and wiring harness different?
> would I need to modify the engine compartment?
> thanks for the help