[Aussie Mike]

Is it just corner of the plenum on the manifold that has clearance problems? Depending on how much clearance you need it might be feasable to trim the corner off the plenum and weld a plate in to give a bit more room. Reducing the volume of the plenum a little won't have much of an affect on HP as long as it doesn't restrict any of the runners.

You could swap the manifold for an earlier version for rego and then save up your $$$ for an 8 throttle body set up.

Cheers