[blue2ki]

i would recommend you get the optra magnum LT because it has ABS, :
1. more power
2. diesel, good FE. + 2DIN system as well.
3. spares are now almost as par with both the cars. mitsu. spares' prices have gone down a lot now. cedias front doors were 20K a piece earlier, its 10K now. outside rear view mirror the whole thing was 5K its 1.5K now.
anyhow spares should not be the deciding factor getting what car.
4. handling - cedia beats the magnum flat out, but still, do you always want to take turns @ 100k's?? i think no. there is a daily drive aspect.
5. comfort - both are good, but the magnum is better on long drives, front and back seats in the cedia have little thigh support, it hurts after a while.
6. get the magnum the top trim, the day you get bored with it, pete it.

by the way, i don't have anything against mitsubishi, you might think, i own a cedia.
even if you go for the cedia, you won't regret it, its a great car. there is no wrong choice here. take your pick.
if you want the magnum get the LT only. if the cedia any trim you like.