What is there (what I can hear) is clean and even
I've replaced cone surrounds in speakers and woofers = I have experience to listen / feel for binding driver coils etc
I'll try driving the unit from another source - from the boot
Then I'll access the unit via rear seat :-) for more detailed inspection.
My gut feel is that (although I'm not a heavy metal fan) that it's there to support the door speakers not to act as a 'cinema' rumble sub-woofer
I guess i'd need to increase size of unit to expect more - bat that's VERY limited in the space above the tank
Cheers
SS

Hi Steve,
I don't know what the output is to the sub-woofer.
I replaced the foam surround in my original sub-woofer and re-installed it.
There are a number of posts regarding the sub-woofer and the search for a better unit.
Regards,
Ed