Thank you for such an informative post.
As per my experience, I got A/C installed in my Mehran '11 model from Punjab Car AC (Lahore). They had two A/C systems for Mehran; Sanden priced at Rs. 29,500 and Denso priced at Rs. 38,500, both with one (01) year warranty. I asked the Owner which one's better? so he asked for how long was I planning to keep this car, I said a year may be. So he told me to go for Sanden and as I said okay please proceed with the installation, he replied it's already being installed and when I looked back to the car, about ten boys had already besieged it and within an hour they installed all the components. The A/C worked really work as I had shades so the cooling effect lasted longer. The Owner did advise to clean the condenser fortnightly and to keep the floor mats dust-free by cleaning them daily to keep the A/C working the optimum conditions.
I believe if anyone needs to get A/C installed in Mehran they should opt for Punjab Car A/C as they provide repair and components replacement warranty. The local mechanics quoted the price of Rs. 25000 but as they don't provide warranty so it's better to go for something which is backed by guarantee.
As for load on Mehran, I got the point in distributor cleaned and got the car tuned which decreased a lot of load on engine and now the car A/C works perfectly in the morning and evening. During noon, it works good and reduces discomfort alot but one may sweat instantly when the A/C grills are moved away from face.
Keeping in view the whole performance of A/C in morning, noon and evening, I would rate it 7/10 and Mehran owners should opt for A/C rather than changing cars because you need to have an extra 50-80K for repair of defects in the next car which usually show up in a two to three months time.
Hope this is useful for someone 
