I followed this order:
Interior
Engine / gear box and other bits in the engine bay
Rear sub frame / diff / prop shaft
front sub frame
You can sort of follow what I was doing here:
http://www.msportster.co.uk/detail.asp?cat=1&offset=0
I took a week off work to take the donor to bits with my brother. It really helps to have someone to help you.
You will need penetrant spray and a breaker bar and possibly a rubber mallet too. I needed an angel grinder to remove some bolts that just wouldn't budge. Dont cut the rubber clutch cable is costs £35 to replace!
Also get a copy of the Bently manual:
http://www.motormec.co.uk/e30.html or a Haynes manual. The Bently is the better of the two but costs more (and is a little americanised). Haynes tends to leave a lot of steps out.
The build manual focuses on the ford donor vehicle - im sure Terry would send you a copy if you ask. All the BMW stuff is photo's on the CD.
The marlin site covers the bits you need.
I've got a box of bits left over and doors/bonnet round the side of the house. The interior is in the shed! I've been getting rid of bits on
www.e30zone.co.uk. I decided to keep a lot of it in case I needed anything.