I have a 04 Optima LX. I just traded in my 04 Sorento LX for a 05 Spectra SX 4 door. That Spectra is almost the same as the Spectra 5.
-As for handling the Spectra wins it. Not as much body roll
-As for comfort I would give it to the Optima. Its bigger inside alittle more leg room and the seats are more comfortable.
-The Optima wins the space catagory.
-Performance would have to go to the Optima.
-MPG would have to go to the Spectra. Right now I have 200 miles on my Spectra and it still has a half a tank of gas. But the Opitma gets good milage too. Last I checked it I got 26 MPG.
The Optima has the 2.4L 4 cyl.
I like both cars equally. What one doesnt have the other one does. You made a good choice getting the Magentis.
Thats my 2 cents.