I am planning on running a 300W or so inverter and soon down the road adding an middle of the road amp (capable of running a 12 or 2 x 10's). My question is, if I hardwire the inverter will I be able to split that same power for the amp when I decide to install it without any consequences? Any info is appreciated.

 

It shouldn't be a problem as long as you are using a distribution block and the right guage wire. You should be okay running all 4 guage and then 8 guage off to the inverter.