The autophoretic change was definitely a retrograde step, and needs regular checks, which is not really up everyones street. The forward facing sections suffer from gravel rash, and the worst section is the double skinned crossmember just ahead of the rear wheels.This will get tiny chips and they will microrust. The black Dinitrol will also tend to mask this process, and that's why I asked for the earlier golden wax 'underseal' finish.

I've added an end cap at each end on the double skinned crossmember, using the exposed bolt end, so no drilling. These are a simple aluminium curved section, lined with neoprene, and stop gravel rash stripping the coating. The other place to watch is the triangular bracing sections at each corner base of the bulkhead. These are double skinned, and obviously between those skins will be bare steel. Because they are touching, so no fancy coating is going to penetrate far, even though each triangle has a small circular hole on the top.

When my GDI was delivered, I began dripping ACF50 into these two holes. The offside is masked by the master cylinder but can be accessed. So I dripped ACF into the hole, to the brim, left it overnight, and the next day it had soaked into the gap. This went on for days. I didn't stop until one morning, the brimmed holes were still brimmed.

I saw a GDI at Brooklands, so a few years ago, and the nearside triangle was red rust across the whole section. Not good.

DaveW
'05 Red Roadster S1
'16 Yellow (Not the only) Narrow AR GDI Plus 4