Hay Sarmad, there are a few places in lahore where you can buy your equipment from. But it comes down to what you would be willing to change. If you're running a the factory headunit (or a chinese android panel), you might want to upgrade to something like a pioneer/sony/kenwood double din. Reason being that the output from the source matters a lot.
Secondly, you can upgrade the front and rear speakers. If budget allows, you can get a good pair of RECOIL components + coaxials for 30-35k (combo). These aint gonna be used and not some crappy local/chinese speakers
Bump up your budget and you can get the nakamichi cs1721 components with the recoil coaxials but would be around 45k. Issue is, for the nakamichi, a amp would be a good idea
The Recoil speakers I mentioned, you can run those off directly from the upgraded headunit ( they will still sound great with a factory unit or a android panel ) and you won't even need an external amp. If you can bump up your budget to 100k, you can have a brilliant setup which you won't ever feel like upgrading from
Will you be visiting Islamabad anytime soon?