Don't bother with any sort of undercoating. It's only for rust prone areas. There's no rust issues in Lahore and Islamabad cars.
I assume you're looking to spend a decent bit of money on accessories and other stuff. Go for an upgraded audio system, high end tires and good alloys if your variant isn't aspire. No need to bother with other stuff besides maybe ceramic coating.
For interior mods daraz china got some silver and chrome bits and pieces to improve the looks a bit from the boring black plastic. They also got steel pedals. For exterior mods it really doesn't need anything, most mods will lead to a paindoo look. At max just go for Chrome handles if your variant is 1.2.
For 1.2 and 1.5 base a screen upgrade to an android auto one may be a wise purchase as well.