I think I can confirm this also. I have just acquired a S3 109 hardtop with a 6 cylinder 2.6L motor in it. It looks original to me and I don't see any mods. I know for a fact it has been off the road and unused for the last 19 years as it is a true barn find. All the original bits seem to be there apart from a missing air pump.

Just to add to the melee, they put the 6 pot in the 109 carawagon conversion which are quite rare. Nice engine but head sensitive to warping. It sounds great. I'd have one but bulkhead not right.