I don't check the forum very often so didn't see the question about 'productionaising' the Micra conversion. All of Dave's points are quite correct and because of the wheel clearance issues, it's not a conversion I would do again anyway. I'm sure there are much smaller calipers that are readily available and would fit inside a standard wheel. I've got some Kia Pride calipers and they are tiny (but they were very prone to sticking when on the Kia, so not much use really!). The Micra discs might be useful on another conversion as fitting them wasn't too difficult, but I will have to find some smaller calipers for the next car. This job however, is lower on my list than sorting out fitting the Lexus six speed gearboxes that I have acquired!
I also have a set of Marina discs that have already been converted to fit A30/35 uprights (came off an A35 van with a Wolseley 1500 engine). They still have the Marina hubs with 3 3/4" PCD studs but I happen to have a pair of 5.5J Cosmic Mk II alloy wheels with the Triumph 3 3/4" PCD, so they are earmarked for 177 CHT which I think I will probably rebuild as a track day car. I've got another pair of 6J Cosmic Mk IIs with 4" PCD for the rear (I'm planning to hack the rear wings on this one to fit the big wheels).
My son Tim's orange A35 'Tango' has 14" wheels so I might try his wheels with the Micra K11 discs, as I can always swap the front suspension between the two cars if necessary.
Steve