Spipe,
After a long time searching the bbs, and net to find something out about this change - I guess you can say i never ever did find anything.
But at the end of last year i bought a set of 4 pots from a bbs RB5 owner, and fitted them on to the front. (what a difference - best upgrade i have ever bought) Falkland Performance did it all for me, and while in there I had a chat with a few of the guys about what would be needed to change the back drums to discs.
They told me that the back axles would have to be changed and back end of the car (suspension wise re-modified) but they could do it. I got a quote for 500 pounds and they had a brand new set of 4 pots from an escort Cossie if i remember, but I decided to just stick with the 4pots on the front. No offence to Falkland Performance as they are great people but it generally costs alot more than what they quote from experience with my car and my sisters Wrx.
From that though it can be done.
Ian

I still want to fit a Blitz induction kit, and a few people on the bbs replied to me and told me how but i lost there addresses.