I've not been entirely impressed with the shallow P3's. Tech12Volt makes a nice under the seat box if you don't feel comfortable doing it yourself.
You'll love that Pioneer double din, I know I loved mine.
The stock mids/highs are definitely not great when you have a good sub-stage, but would work for a while if you didn't want to upgrade them yet.
If you're going with a Cadence amp look at the ZRS-C series, my buddy runs 8 of the ZRS-C6's and has had good luck with them. I'm not a huge fan of their newer stuff, as I loved the old A7's but they aren't bad by any means.
You'll love that Pioneer double din, I know I loved mine.
The stock mids/highs are definitely not great when you have a good sub-stage, but would work for a while if you didn't want to upgrade them yet.
If you're going with a Cadence amp look at the ZRS-C series, my buddy runs 8 of the ZRS-C6's and has had good luck with them. I'm not a huge fan of their newer stuff, as I loved the old A7's but they aren't bad by any means.