Budget building with room for upgrades

[brewops]

I've been reading and researching my options to upgrade the stock sound system in my '15 Nismo for a few weeks and came up with the following plan. The idea is to come at it with decent quality a step at a time, leaving room to expand to accommodate a different HU + backup cam, maybe some new tweeters or a set of components.

-Cerwin Vega 104 - 10" 300w RMS sub (had this already)
-Smallish truck box to fit below the support bar
-Lanzar OPTI6PM set, already installed
-Precision Power P900.4 amp under the seat
-PAC LOC

Since I am not so sure I could push those stock tweeters very hard with the amp, I am thinking of throwing those on the HU front channel. Then use the LOC to the AMP off the rears with the Lanzars on the first 2 channels using the other 2 bridged for the sub tuned down appropriately so I'm not over powering the 300w RMS sub with 450w RMS. Does this sound decent? I thought of returning the Lanzars and going for a set of components right out of the gate, but they're already installed as I didn't really think I could find a decent 4ch amp for under $200.