So some modifications to the assembly are required to do this.
The 5th gen assembly……
Firstly, remove the motor and place something so that there is some space between the metal roof and the runners, so you don't accidentally chop them later.
A few bits need cutting off to enable it to fit under the 4th gen roof, after the angle grinder...
Remove the headlining from the car, you’ll have to remove the interior light, sunroof visors and grab handles before the headlining pulls off to reveal…….
Unplug the electrics for the old roof, the rain water drain pipes and undo the eight 10mm bolts that hold it in place.
At this point you can just drop the old assembly from the car.
A comparison of the 4th gen v's modified 5th gen sunroof assembly (4th on the left).
A bit of work is required to make the 4th gen interior light fit, just cut the bits as shown in the picture below.
The rear lip was required to be cut off so to fit the headlining.
I did this with an angle grinder, but would have been better doing it with an oscillating saw, like the ones they use to cut plaster casts off. You’ll get a cleaner and more controlled cut.
And the assembly bolted onto the car, the existing assembly uses shims to get a good fit, so you may have to play around a little with these to get it sitting flush.
A bit of hindsight would have helped here, as you can see the lip on the front of the sunroof assembly sticks out a little too much, this'll need cutting for the headlining to fit perfectly, if you cut about half the lip away from the front, you'll get a perfect fit.
Here it is from the outside, looking a bit dirty.
If you have the rear prelude light, you will also have to remove this little piece from the motor area.
Then cut a portion of it away.
And you can see here why this was necessary.
Due to the sunroofs having a totally different mounting method for the rear headlining, some work is required to make it fit. First some of the mounting brackets need to be snapped off (4 of) you can just about make them out in this pic (top left and right and either side of the prelude light cutout).
Then it’s a case of working out a way of attaching the lining at the front end, to do this I came up with the idea of using the front headlining as some sort of support and fitting brackets so that the rear can slide onto the front before you clip it in place.
The brackets are a little rough, but do the job quite nicely. I will revisit this at some point in the future, I think the best way will be to bond some push clips to the headlining in the relevant place so to replicate the OEM fitting method.
The guides not quite complete, I'll update it further soon.