Turns out that some of the "affected" models will require more than just a quick, easy (and free) software adjustment to placate Uncle.

Actually, it is most of them.

Of the 482,000 diesel-engined VWs identified (so far) for the High Crime of end-running Uncle, 325,000 of them may require physical alterations; that is re-engineering of their hardware. Specifically, they will probably have to be retrofitted with urea injection – a "feature" VW diesels up through the 2014 model year uniquely lacked – and which was probably among the reasons why people chose to buy a VW diesel.

More on that in a moment.

Urea injection is a chemical (catalytic) exhaust treatment that sprays a fluid – urea – into the exhaust stream. This alters the composition of the resultant gasses issuing from the tailpipe, making Uncle happy. It has become unavoidable to have this system, in order to placate Uncle. Every diesel-powered passenger car sold in the U.S. now has it – including all new VW diesels.