What is the stock sub size in the element and has anyone replaced it with a beefier one?

IIRC it's a 6" made by Alpine and it's pointless to replace it since its dual voice coil and specifically tuned for the enclosure space it's in - AFAIK there are no replacement 6" DVC subs out there.

A better approach would be to replace the whole unit with a JL Audio stealthbox. It has a 10" sub all ready to rock and fits in place of the factory unit.

6 inch drivers exist, but the DVC is the killer. Maybe you dont need a dual voice coil model for this application.

Theres a bunch of them at Parts express, but I only found one that was DVC, and its pretty low end:

http://www.partsexpress.com/pe/pshowdetl.cfm?&DID=7&Partnumber=290-352

Theres some great brands out there though.

The Stealthbox is an excellent choice, but sheesh, its kind of expensive.

You've got to wonder if that's the same part used in the E. But I seem to recall the front face of the sub being flatter that that one when I removed the shroud to do the 12v socket wiring work.

-brendan