I was in need for a stabilizer (copper wire) a few months back as well, and had to go through a lot of shops over phone and in person after searching on Internet.
One business dealer (importers of power conditioning equipment for business contracts) I ran into was "Ali Business Machines" in Blue area. The owner was an extremely pleasant and courteous person, even though their targeted customers were large corporations and not domestic consumers. The budget stabilizers they had were hunky chinese made servo stabilizers (Copper wiring). Unfortunately, at the time of testing in their warehouse/lab, it was not working at the voltage range that was required by me (160v) so I did not buy that one. If your required voltage range is about 170/180, then you can call them up. Keep in mind however that servo motor stabilizers have a slightly slower "response time" compared to relay types, but the former do provide constantly stable volts in a narrow range. The 5000va one was in 18-20k range however.
If you require lower voltage model and/or a bit cheaper, then you can check out Ghazi Electronics on College road. They were recommended by two different people (including Ali Business owner) and they offer different models depending on the wiring (copper/aluminium). I went there to buy their own locally made 7000va copper ralay-model (was around 11-12k if I remember correctly), but instead got a chinese brand "Delux" (apparently) servo motor 5000va (comes out to about 4200W) for ~14k at that same shop. I have been using it to run a 1 ton AC, a small fridge and a 1000va UPS (which runs a fan, energy saver, computer and two routers) without a problem. It works down to 160v, but keep in mind that it doesn't cut off output if the input voltage gets even lower than that (which is common to most stabilizer in this range however). They also make custom-ordered stabilizers, but their generic models would suffice in your case.
Universal used to be extremely reliable and of good quality, but I have heard from at least one person of an anecdote that they are using aluminium nowadays. Can't verify it either way, but an alternate reliable brand suggested at that same discussion was "Rimco" which ought to be still using Copper. They don't have a dealership in Rawalpindi/Islamabad however, and they said they can't deliver from their factory either, so you will have to take a trip to Gujjar Khan to get that one, but I don't see the need for it. All of the above mentioned stabilizers have the same chance of being using Copper, if not more, as will this brand.
Best of luck in your purchase. Do share your experience afterwards.
