I've bolted some more stuff on.
For a short while, the engine looked like this:
Hiding somewhere in there are my injectors, which I had cleaned by a company called Big CC. They build properly ridiculous (mostly) turbo motorcycles. If your injectors need a clean (mine did), it's worth a trip over to Wokingham just to check it out. They're not overly pricey either.
While I was there, I also deleted the wiring and plugs for the right hand MAF, EGR valve and Fuel vent guff, got one of these:
which now lives here:
That now reads inlet air temperature.
I then had a cock of a time for a while. There are two vacuum take offs for the brake servo at the back of the throttle bodies, attached to which are (unsurprisingly) two vacuum pipes. These go into a T-piece, then to the servo. The pipes also turn hard over time and split when removed. At just short of £50 to replace (with original BMW parts) I thought sod it, I'll just cut them down. Even using lube, they were a right **** to get on, not helped by restricted access. Efookin'ventually they were on there:
Next job, pop the cam position sensor plugs on, fit the bracket which supports the engine harness trunking on. Job's a dream. Except, it wasn't! The bracket was in the way of the cam sensors, and the sensors were in the way of the bracket bolts. Arse! Anyway after a bit of a sweary fight, with my hand jammed down the back of the engine, I got the buggers all done. Just plug the knock sensor plug into the bottom of the trunking, bish bosh, done. Except... with the vacuum hoses sitting further forward, the knock sensor plug needed re-routing under the pipes. No problem. Well, I say that.. There wouldn't have been if the sensor wiring was 10mm longer. As it was, I had around not enough bloody space between the trunking and the plug to get my fingers into (at an awkward angle) to guide the plug home. Bugger! After some more swearing, it was done. Just the new ICV balance pipe to fit between the throttle body banks to do and I could bolt the plenum on. Yep, what a twat that was! Tight as fook! It all felt like some kind of crap test of resolve or something!
Aaaanyway! I bolted the plenum, bell mouths, plenum lid, airboxes and tubes on, poured some fluids in here and there, turned it over in 15(ish) second bursts with the plugs out and sparky stuff disconnected until the oil light went out, turned it over a few more times and plopped some plugs in. Then I bolted some more stuff on, turned the key and......
It made a good noise!
I initially thought there was an air leak as the tickover was a little irratic/rpm took a while to die down properly, but seeing as the heads are now flowing a bit more air I thought a bit of driving might settle things down. After just a few miles, it seems to be doing the trick.
Some of those miles were driving to Coopers BMW in Banstead to get an MOT this afternoon. The bugger boiled up on the ramp after a while ticking over, nearly giving the tester a boiling shower. The test was aborted. I planned to drop the coolant out and put fresh in there, so just had straight water in there. There's a decent chance of an airlock too I guess. The old girl's front end is up in the air now ready for a flush through/bleed/fresh anti-freeze, which I'll do tomorrow hopefully. On the up side, the guys at Coopers were pretty into the car, which was cool. It was also pretty cool driving it for more than a mile without it knocking its tits off!
Hopefully I'll be holding an MOT certificate in my hand tomorrow!
Can't wait to give it some proper stick!
Cheers! Dave.
I best get to a private test track eh! 
So now wearing a 1.5 bar cap, and with anti-freeze, it's (unshockingly) holding it's water a lot better. 
It's turned into a long read! 
I took the old girl out for a drive down one of my old biking roads. Nice and open with lots of roundabouts. Even short shifting at around 5k (I haven't sorted the tacho yet), it's a LOT of fun!! One thing though, is that the gearbox is pretty noisy. Hopefully this is down to the oil being too thin for the lightened flywheel. They're known to cause rattle. I've got some thicker oil coming, so I'll know what's what during the week I hope!
The parts are listed on the zone facebook group. Search for "Dave Smith"