I am getting ready for an upcoming competition and currently i am running my 4 hdc3s at 1 ohm off a 3500d.1. I'm not 100% positive what the impedance rise is but I would guess it would double in my enclosure. I was thinking of running the amp at .25 ohms for the competition (never daily). What are your thoughts and what is the maximum time I should burp it? Thank you.