My Mehran is installed with an aftermarket AC SANDEN (genuine) compressor, which I got in April/May 2007 and is working trouble-free till now, Alhamdulillah.
Only minor maintenance tips, like getting blower serviced atleats once an year and getting compressor/radiators jaali cleaned by blower and pressure water and checking keeps your car running good and AC cooling good. Also add coolant to radiator.
It costed me 17k when installed. At that time DENSO was 27k as it was short in market.