Optra is no doubt a great car especially for the one who really wants to own it. But as per others and me, I would say that you should decide this depending on your usage.
I mean it depends on your travelling and routes. If you are a long drive traveller or can say travel a lot here and there. Especially in any remote areas of the country than I would suggest you to stay away from these imported thingy.
Because whether it will be an Optra or any other imported car you will be in deep **** if your car broke down somewhere in any remote areas like deep Punjab, Kashmir etc. Because in such areas you won't be able to find even a simple part of it. And for such conditions my suggestion would be to go no other than a Toyota.
And if you are a city guy and not much travel away from the Motorway or Normal Highway routes than I would suggest you to go for it and I am telling you that you won't regret it. Because it is built for it and you will be amazed by its drive, comfort and safety.
As for the parts, yes they are expensive especially the genuine GM marked. But now a days many other third party low price and decent made parts are available in the market for it as well. But keep that in mind that these third party parts are ok for temporary use but not as a permanent parts. Optra is best stable and remains good with its genuine GM parts.
Some major or you can say big parts that doesn't required to be equipped on daily basis are sometimes hard to find but again can be arranged and booked directly from GM Motors Karachi. And can be delivered in both normal and agile delivery routes, depends on your pocket and urgency.
Other than that all I can say about the car/ ride itself is "Really Awesome".