Speakers for Heavy Metal

VMPS ?

Hard Rock and Heavy Metal are very difficult to reproduce in our home systems (for an unknown reason?).

Few audiophile speakers can get it right. I tend to agree w/ the above advice and would add for consideration, B&W, Infinity and Thiel, loudspeakers.
These would be from the 1990's vintage.

Also, Klipsch Cornwall or Cornscala are excellent for Rock music.
The cornwall is a very large speaker that requires a larger space to stretch out.

Back in the day I worked at a Klipsch dealer (and met Paul once) and though I was not a big fan of his speakers, they are "the bomb" when it comes to rock and roll.  So I agree with some of the other postings about snagging a pair of Cornwalls.  If you can accommodate a pair of (corner installed) Klipschorns, that would be even better.  Both are really excellent at rock and roll.  I would not say the same for the La Scala, they don't seem to have the same "punch" and "extension" in the bass, but you'll probably enjoy the Corwalls or Klipschorns.

I listen primarily to ambient/lounge/chill whatever and metal.

Run some frequency sweeps.  Here is the one I use::

http://www.audiocheck.net/audiotests_frequencychecklow.php

The guy actually calls out the frequencies so you can see where your system is lacking.

Ideal response would be as flat as possible down to 40Hz, as that is about as low as metal gets bass wise.

In my situation, I have Totem Arros in a small room, and through mass loading and careful positioning with respect to the back wall I am able to get surprisingly good response.  Otherwise, I would peruse the various publications that show measurements with bass down to 40Hz and shortlist those speakers for auditioning.