As I understand it the main differences between BOA and BOB are mechanical being different profile cams and a duplex chain instead of simplex. Both BOA and BOB were all fitted with slush boxes as standard and as far as I'm aware were only fitted in Granada/Scorpio models. BOA fitted with BOB cams gives more power than stock BOA but not more than BOB. BOA gives 195 BHP at 5500RPM in stock trim. Electrically there is little difference between them.
As for gearboxes I would say go for a MT75 hybrid, the type 9 is reputedly good for 200 BHP but has a nasty habit of releasing its internals above this figure, with just a sheet of 1.2 mm ali between the box and your legs would you really risk it? MT75 hybrid needs to be made up from a V6 XR4X4 box and a 2 litre box, essentially fitting the internals of the 2 litre box into the V6 front casing, I know I've done it (although I'm about two years late with writing it up
).
D.