You have a good headunit and amplification. Kenwoods usually have a warm signature tone compared to the likes of Sony and Pioneer amplifiers. If you are aiming for a SQ setup (be it a beginner setup), my suggestion would be to ditch these components. Instead, you can easily get yourself some infinity referance or jlb gto components. If you can spend between 30-35k, I'd suggest you get the Helix F62C (their mid tier 2 way components). Haroon Radio in Karachi stocks all three of these components
As for the sub, ditch it. The 307 was a great sub back in the day (hell I was running 4 of them for a short period of time) but it's not a sq or even a sql sub. Get a jbl cs1214 or the more similarly matched jbl club 1214 or infinity reference 12 sub. Put them in a 0.75-1 cu-ft sealed enclosure and fill it with polyfill.
I'd ditch the rear speakers. SQ setups are usually front stage focused. If you still want your rear fill, run the rear speakers directly from your headunit. The 4 channel amp is good for your front stage components and sub
