Has anyone upgraded XF subwoofer? Please send details on equipment and process. It just needs a little more punch on the low end.

Where exactly is the sub, BTW?

Under the spare tire.

2009 JAGUAR XF Parts - Jaguar Parts Center - Call (800) 510-1401 for Genuine Jaguar Parts and Accessories

I have the 400w system(non BW). I have been thinking about adding OEM subwoofer in my '12.
Does anybody know if it would be a simple plug and play?
I check the spare tire area and there is a harness for the subwoofer. I am thinking it should be easy install.
Would i have to add an amplifier or anything?