Many Thanks for chipping in with your reply, I agree finding information on these particular fuel assemblies is challenging !
It would appear there are two fuel assemblies as indicated here, (ooh cannot post links under 5 posts) there are two shown on the "opposedforces" website which lists part numbers
I have a 42021FC010 which has a red sticker on with this part number displayed, which appears to be identical to the one displayed in your pictures which needs splicing. The later revision 42021FA310 does not need splicing according to pictures that pop on when searching for this revision.
I'm debating whether to just bite the bullet and pick up a later fuel assembly, one further question I have if you don't mind, I like the point regards using butt connectors if I attempt this I will use them, did these or the heat shrink you use needs to be specially fuel resistant or these were just regular off the shelf parts ? was just concerned with fuel melting away the plastics.
A good resource I use for research is the "scoobynet" forums based in the UK as a fair number of JDM imports are on our shores, not sure if linking to other forums is considered appropriate but google will find it. Cheers