Bhai ... it is always a matter of happiness for me to communicate with friends ...
You have asked several questions .. so let me respond to them in the same order ..
- Essentials >> It is important to first determine what you want ... that makes the difference between luxury and necessity ... First essential is perhaps to change the tyres and rims .. this is what most Corolla and Honda buyers do. Buy good set of polish, wax, glass cleaner and Son of a Gun. You will need to get mats .. In my case, I have 3-D mats and then covered with transparent plastic mats. Perhaps a leather steering wheel cover ... My advice is to pick up a thread like that of Laadli and see what you deem necessary.
You will need to have a good crook lock, security system, etc.
Corolla does not come with a good audio system ... Even if you stick to the very basics, you will need to replace the rear and front door speakers ... if you intend to proceed further, then sky is the limit ... If you need my feedback on this, first you should have some budget in your mind ..
Incidentally I started my thread when Laadli was already about nine months old, so none of the basics have been covered in any detail ...
I suggest you look at these threads
https://www.pakwheels.com/forums/body-work-interior-paint-glass-appearance/160274-1st-service-polish-my-ride-corolla-2011-a
https://www.pakwheels.com/forums/body-work-interior-paint-glass-appearance/145296-toyota-corolla-modification
https://www.pakwheels.com/forums/members-member-rides/156473-my-toyota-corolla-gli-2011-a
You will find good information in the above threads .. if you have questions then I am here to answer those ...
Tyres ... I have been using dB Series Yokohama tyres ... I am using 205 size, but if fuel economy is a consideration, then you should stick to the stock 195 size. dB series tyres are very quiet, but in my observation, they dont perform well in muddy and slippery conditions ... Like everything else in the world, there is no perfect tyre .. it all depends on your choice and budget.
I got my CNG kit installed by Toyota Islamabad Motors for 42000 .. now they charge 52000 for the same kit. My car does not have any problems in more than 11 months of use ... however, you need to check threads on PW about this ... I have heard many people say that CNG installation damages the head ... but since I have not faced any problem ,,, I would say it works excellent on CNG
CNG Partitition .. it is not available ready made. I got it made from a shop in Fire Brigade Islamabad. Mine is made of ply covered with carpet like fabric .. If you do not want to install amplifiers etc on this, then ply should be good enough. However, for future installations of any equipment ... then perhaps you should consider partition made of 1/2 or 3/4 inch MDF. I have removed mine, if you are interested, then PM me.
ECU cover>> I bought mine from a Toyota dealership in Lahore, but recently I got one for Dr. Tanveer from Rawalpindi Saddar... just go a few pages and you can see. This one is better than the one i got from Toyota dealership.
Fog lamps >> Depo is a good brand and available everywhere.