I have a similar set up but I have J&M Rokker speakers, I grounded the 300x2 to the -ve terminal on the battery as per Rockford Fosgate recommendation and this set up has been running flawlessly for 10 months and it HONKS!!
bTW set the 300x2 amp at HP (NOT AP!!!) and my gain is at 5 - very important!
You'll love your set up. Good deal!!!

 

I used the Fosgate power kit ordered from Amazon. You can cut the power cable in half and have plenty of length to run it back to the (-) terminal on the battery. Grounding to somewhere other than the battery may work, but it specifically state on the Rockford Fosgate website to use the battery as your ground.

 

I read ultranutz install direction sounds detailed enough to me, anyone have anything to add?thank u for the install directions ultramutz

 

Very reasonable thanks!

lp

 

O yea had free shipping on part of it also took off like 15 Buck its 5 to 8 days instead of 3-5