The M30B34 intake manifold is supported by two struts that bolt to the valve cover and a small bracket between the block and the bottom of the manifold.
The M30B35 does not have those ugly struts above and is instead supported by a beefy aluminum bracket connected to the engine mount.
The shape of the E28 engine mount prevents the aluminum M30B35 bracket from fitting.
Here's what a B35 looks like:

This pic shows the M30B34 bracket, along with the correct motor mount. The B34 bracket will not be as strong; on the B34 there are additional supports holding the manifold in place at the top of the manifold.

This is the problem: The motor mount is in the way of the M30B35 bracket:

This bracket needs to be about 23mm ‘shorter’ so that the nut for the engine mount can secure it above the mount (top right hole).

Other's have butchered both the engine mount bracket and the intake bracket to make this work. I'm not into butchering such things.
I also know the intake manifold is not likely to break on it's own. However, I am not ok with not having it supported. I figure some idiot some day may attempt to leverage the engine with the mainfold...which is probably why BMW designed it so heftily (sp?).
Planned design (may change as I refine the design):

