OK, So I finally got the M54B30 manifold installed on my M52TUB - here I'll attempt to do a bit of a write up to see if it assists anybody. I'm sorry I can't remember nut and bolt sizes but I will have a go later and edit them in. This is a work in progress.
The order below is not necessarily the order you have to do things in. I take no responsibility for you breaking things
Things to do before you start
Probably best to pull the fuel pump fuse and turn the engine over a few times to clear some fuel out of the engine - I didn't do this, I should have done and I probably wouldn't have ended up making such a mess. Remove the pollen filter housing at the back of the engine bay by removing the four hex bolts.
Remove the engine battery cable from the little box near the left hand strut of the motor.
Remove the cover over the top of the intake manifold by removing the two bolts that hold it on.
Remove all the stuff
Remove Air Filter Housing (couple of bolts on right side of air box), MAF (pulls off), DISA Valve (two bolts, then it just pulls out), Lower Intake Boot as well
Twist the two plastic clips to remove the plastic shield in the top right of the engine bay to get yourself more room (like the picture above)
Undo the two bolts below the DISA valve (and above the throttle body) that attaches the metal throttle body bracket to the intake manifold. Behind this bracket is the idle control valve. Also undo the nut that holds the wire on (as shown in the photo). You should also undo the bolt holding the oil dipstick to the chassis (you can see this has been undone towards the center at the bottom of the photo).
The throttle body is held in with 4 bolts, remove them and pull the throttle body out. You should also unclip the throttle cable from the throttle body as you pull it out. Here are a couple of pictures of the throttle body. We'll call this throttle body porn.
The CCV is held in by two torx bolts on the left hand side of the throttle body. It is a bastard, I undid everything and couldn't get the intake manifold off until I realised I'd left this on. So probably best to undo this now and save yourself some stress later. I don't have any photos of this as I was spending most of my time cursing and questioning why I started this and didn't have time to take a photo.
Look under the manifold and below where the throttle body was there is a single nut which holds a bracket for the intake manifold to the chassis. Remove the bolt.
Fuel Rail, Injectors etc.
Undo the VANOS Solenoid plug and the Vaccum tube going to the fuel rail. The black wire harness box which connects to all of the fuel injectors is held onto each one with a little clip. You undo the clip by pushing one side of the clip down to the side from the top. Once this is done, a tug will pull the harness cable up, you can then move this out of the way a bit.
Stick a rag around the Schrader cap at the front of the fuel rail and push to release some pressure on the fuel rail. Remove the 4 fuel rail bolts. In theory, you should be able to pull the rail up, the injectors should stay in then you shouldn't lose any fuel - move the fuel rail so it's not in the way when you want to remove the intake manifold.
Remove the nine bolts holding the intake manifold to the cylinder head.
On the intake manifold, by the firewall there is two vacuum tubes connected to it. One is a thicker right angle hose and the other was a thinner hose which I think connects to the air pump - pull them out.
You should now be able to work the intake manifold free a bit. To get the manifold completely removed, there are two pipes underneath that need to be pulled, you'll also need to unclip the battery cable from the manifold and feed this through the manifold as it comes off.
This is the point I resumed the project on a pissing down Saturday and wondered if I'd bitten off more than I could chew.
And a little money shot of the manifold with the throttle body adapter on.
All in all, I could do this quicker now, I has a few issues, such as the CCV hose snapping and knackered vacuum hoses, so its definitely replacing all hoses whilst your in there. It's also the best time to replace your VANOS oil feed.