I'm getting ready for more audio upgrades as well. Currently have Focal separates in the front and focals in the rear deck with a JBL MS-8 amp/processor. Thinking of a Zed Leviathan III and a single 12" sub. From what I've been reading on the car audio forums people aren't using caps any more. This may be due to the more efficient class "D" amps, not sure. I haven't been into car audio since the early 90's so I'm learning all over again.