This is awesome! Ever since Vikash put out the code for the first-gen Legacy I've wanted to try this, and now there's gonna be an SVX version.
Sadly I don't know any assembly so I can't be of much use except as a beta tester. I've got an old omnibook sitting around with the proper port, I just have to make the Serial->SM plug for it.
I read through the info on your site... I'd say SVXride is right. At least for the fuel maps, you should try to get in touch with Longassname. He's written his own for the SVX, so I think he's the resident genius in that field.