How Well Would These work together on the stock NonJBL HU?

Looking at keeping the stock non JBL Entune Nav HU but improving the sound some. I am looking at something like this
https://www.amazon.com/dp/B003VVYL4...UTF8&colid=18V1R3NKNG1O&coliid=I3N5263NFQ0CZT

and a powered sub like this
http://www.crutchfield.com/p_777B8PTD/Sound-Ordnance-B-8PTD.html?tp=114

I like that the units are small and fit under the seat. I dont want bumping sound, but do want to increase the quality. I will also be replacing the door speakers. I am not sure if I would just power the fronts or front and rear with the amp.

THanks!
DAVE

 

Sounds like a decent set up from what you are looking for.

 

45x 4 will def be an improvement. Not much but enough to notice and be satisfied depending on how much more sound perfomance you are needing.

Make sure and choose speakers as close to 45 rms as you can, prevent some clipping and overheating/distortion.

I kept the stock hu also. I chose to power all 4 doors, but from the front seat you cant hear the rears at all. Ive thought about powering the rears off the hu and bridging the fronts for more power but im going to leave well enough alone.

 

If you do not have passengers in the rear very often then down worry about the rear. And in all honesty, you are upgrading the sound for you, not your passengers.

I went with all 4 doors but i only amplified the front set.

 

Thanks. For the powered sub, that would have to tap into the speakers before the Alpine unit, correct?