The arrival of rocket launchers as extremely light-weight missile weapons and Light engines makes it much easier to abuse the AC20 quirks on the AH. This particular build uses a lot of things with '20' in the name. Just chainfire the RLs and you'll be fine, even with groupfire it only takes like 50% heat. Downgrade RLs if you need more ammo or speed. Don't take the UAC20, the jams are yucky and the regular 20 gets a 20% cooldown bonus.