Dinu is right, the dual exhaust is totally unnecessary for all four-cylinder engines. The four cylinders are 90 degree out of phase to each other: the first compress the fuel mixture, the second is expanding from the burning gas, the third evacuates exhaust gas, and the last aspire the intake gas, and it's rotate around. At anytime there is only *one* cylinder that rejects its exhaust gas, therefore one exhaust line is enough. And beside that, the 2.0-2.3L has 4-2-1 exhaust manifold before go through a common catalytic converter. Adding another exhaust is a waste of money, weight, maintenance cost, ...
If someone wants the cool look of the dual-exhaust, why don't they better use a pre-smoked tail of the pipe as fake exhaust. It's certainly a cheaper solution.