When Volkswagen submits its plan to fix diesel cars that cheat on emissions tests on Friday, it really has just two options for most of the vehicles.
It can install a bigger exhaust system to trap harmful nitrogen oxide or it can add a chemical treatment process that cuts pollution. The bigger exhaust will likely hurt performance and gas mileage, while the chemical treatment needs a clumsy storage tank and has to be kept warm.
And experts say both will be expensive.
See Friday's Arkansas Democrat-Gazette for full details.