Mine is an ex with a subwoofer but non Navi.
As some members' recommendations, I decided to keep using the factory amp to power the speakers and tweeters which saved me so much time to do wiring on crossovers and amp.
Front speakers, the top of the JBL line, GTO Stadium 609C (bought it for 60%off from amazon Canada miraculously, the last item)
Rear speakers = Hertz 2 way coaxial basic speakers
So far, I m happy with the front speakers and tweeters. It did really make a big change in terms of clarity. mid bass seems slightly richer too.
I mistakenly broke the right A pillar door clip(triangle) which is known to be fragile but unlike the B pillar clip, it seems to be 4 times cheaper ($12 usd on honda parts vs $ 49) but it's held on to the door pretty well. Maybe I will buy it if I have to buy other stuff to save shipping cost.
I didn't do any sound proofing or dynamic stuff. I indeed purchased some thick soft cushion like rubber sound dampening (2cm thick) and maybe I will apply them later to see if it would make some difference.
So far, the sound is much more clear.
The subwoofer part is not satisfying my need. Hence I started installing an 8 awg amp kit yesterday and an android headunit.
I will post that on a separate post as I m having some difficulties (no sound)
I think JBL is good for the price but I really want to try Infinity Perfect series when I make more money.