Agree with the fact that prices have gone up. Glad you're utilising the old stuff you had with you. I just don't agree with the way your installer has wired up the setup. He's basically done jugaar by running two different types of speakers that have different specs on the same channels and then using a cheap rca splitter to split the channels. That's a good recipe for disaster if you crank that volume and clip your amp. Do you have a fuse on the powerwire?
1 more thing. Sealed boxes make tight punchier bass and they don't go loud like ported boxes. Pioneer subs ain't exactly sq subs but you can tame them if you put them in a sealed box. You won't have to suffer from higher freq bass notes especially if the sub is in a untuned box
Regarding your revo, I'm running a pioneer 6704 with a Helix high to low adaptor powering my old JBL gto608c's which I got in 2015 and a pioneer 2500ls4 in a 0.6 sealed box behind the seat. Did a basic sound treatment around the speakers in all 4 doors including fast rings. Even with the factory crappy android unit, the sound quality has completely changed inside the cabin
If your polk coaxials are two-way and biampable, you can always install them in your revo too. Anything is better than the crappy paper treated speakers these cars come with
Wiring an aftermarket setup is fun. It's easy and not that much of a challenge even for a diy'er 
and there are a few shops around islamabad/lahore/karachi that do a pretty damn good job in installing and tuning setups
