i have seen the complete thread and suggestion posted by experts. i believe budget is the main constraint otherwise options that are laid down are better than what is intended purchase by Nabeel Bhai (Sony/kenwood). If he has chosen sony gt1201 or kenwood 310 then price approx 4k. To run one of these woofer doesnt required somewhat HIFI or MONO but a simple two /four channel amp can serve purpose on bridge mode. I see that pioneer subs are above 5500 and are far better than the one's that Nabeel bhai quoted. Further JBL gt5-12 is further more integerated than pioneer sub so the more you go high, the more budget you require. i suggest Nabeel bhai to share the complete setup or Intended setup so that suggestions could be laid down before him to choose that should be budget friendly and have nice sound. Yet on the other hand i believe to spend one time on good stuff instead of going for cheaper models and spend more money on upgrades.
so my suggestion is to go for a second hand amp four channel that should play one sub along with one set of speakers to balance it out. If and only if Sony gt1201 or Kenwood is option for Nabeel bhai then i suggest to go for Kenwood as it hits hard and pays back more in terms of performance. Total expense will not be more than 12k in this case. Rest is the owner's choice ofcourse 
