Firewall for Trunk w/ Nitrous and battery!

Thanks for all the input, I think I'm just going to do it all, firewall = Sheet metal, Battery = Sealed & switched, Nitrous = Partition and vent. A few extra pounds won't kill me but trying to shave them in this area just might. It is only street legal's so the inspection and rules are pretty lax until you get into the 11's. As far Battery on the right, it weighs about the same as the nitrous so I think that's only relevant without the bottle.

Here are the rules from my local track for this class.

* Regarding Nitrous Oxide (NO2) - The use of Nitrous Oxide is allowed in all Street Legal classes provided that any Nitrous bottle located in the drivers compartment be equipped with a pressure relief valve and vented to the outside of the vehicle. All Nitrous bottles must be securely mounted (plastic mountingbrackets not allowed), be stamped with and meet the minimum DOT 1800 PSI rating and be clearly identified as Nitrous Oxide

* All batteries must be securely mounted (no bungee cords, rope, wire etc) Batteries may not be relocated into the driver or passenger compartment. Rear firewall mandatory when relocated battery in trunk. If sealed battery box is used, must be vented outside of body. When battery is relocated a master power cut off switch must be installed on rear most part of vehicle.