no dude, you're fine. After you get to 1000 or more, then a cap would be needed. But it's not like it would hurt. And 150 is wayyyy too much for a cap that you would need. What is it like 5 farads and digital? Theres a rockford fosgate cap for sale on here i believe its like brand new 60 bucks, digital, 1 farad.
And is that 600 max RMS or continuous RMS?