Few questions please peeps on the history of a GC8 STi type R or RA with DCCD.

Firstly, I read this on on importer's website:
"Since April 2004, a model report has been required when SVA testing any car of newer manufacture than Jan 1997. Although there are model reports for Sti 7 & 8 models, there are none available for the classic STi Imprezas. This mean that only pre-1997 Imprezas can be importd to the UK."
I don't understand this, does this mean that if you wanted a V5/6 Sti you would have to say that the manufaturer is unknown, and register it on a Q plate!?

Second, as I understand it, earlier STi engines had a closed (or semi-closed) deck engine block, and later ones an open deck block. When did this change occur (v3 or v4?) and did it coincide with the red coated inlet manifold and larger intercooler i.e. can you identify an open deck one by a red inlet manifold? Does anyone know why this change occured, was it for manufacturing reasons, cooling or what, seems a backward step? How important is this, I have been told the earlier colsed deck engines are superior, OK I know there are many other changes which make the later ones more powerful but I am talking for a rally car which will be fitted with GEMS management so I'm only really interested in inernal differences.

Final few, on what version STi did the 4pot front/2 pot back brakes appear? How can I tell if it has a front helical diff or not becuase as I understand it this was an option on v3/4 but then standard fitment of v5/6? And when did the dashboad design change to the later type?

Thanks a lot...

 

Hope i get this right:
1
Closed deck stopped about V2.
My V£ is an open deck.
2
Red tops started about V2 and V1 Sti maynot have red tops.
3
Red top does not = closed deck.
4
Open blocks are cheaper to make than closed, hence the change
5
Closed decks are inherently stronger, though my V3 open runs 1.4 bar and about 400 bhp

Graham.