Just posting for posterity as I no longer own the car, sadly.
The 3.0 did go in successfully with no modifications to the mounts needed - reading iancav6's post above, it looks like the fact I also fitted an F28 helped me as I didn't need to do anything to the bonnet support.
However, I was absolutely determined to preserve the multiram system from the omega, so I came up with this:
A lot of messing with silicone tubing and aluminium pipes! I made a 'T' section to split the intake tract out of two chopped-up air mass meter housings. Obviously no room for an air box so I put a cone filter behind the bumper as iancav6 did. It was all a very tight squeeze.
The hardest part to find was the flexible ducting between the TB and the two intake tracts. They turned out to be essential as I lost my engine stabiliser bar and couldn't find a replacement, so there was quite a bit of engine rotation under acceleration. You can see the rusty part on the top of the hose clamp for the right ducting, where it rubbed on the bonnet support.
The air con had already been ripped out of my Cav but the vacuum reservoir was still there, so I used that to plumb in the multi-ram valves, though I never got around to making a controller to operate the solenoids. You can see a red zip tie near the bottom of the picture, from when I was experimenting with the different valve configurations. Opening the lower valve improved the pull at high speed and didn't seem to hurt the low end.
Just posting in case anyone else is considering this project - well worth putting in the time to build an intake that preserves the Omega intake system. I realise what I made was a kludge, but it seemed to work well.
Your post was held in the moderation queue because you posted an image before you had made 10 posts as per our T&C's. I have approved it for you this time.
T9 man