Kelly, the firing order is the same as the "new" Ferrari V12 firing order that commenced with the 456M engine. But BMW number their cylinders backwards from Ferrari. Ferrari always start with the front right (when facing flywheel) as #1, then go sequentially back to the firewall for #6 (right rear), then horseshoe around so that #7 is also at the firewall (left rear), and #12 is the left front.
BMW on the other hand have the rearmost right as #1, then the frontmost right is #6, and the frontmost left is #7, and #12 is the rearmost left. A picture is always worth a 1000 words, so here's a diagram of the two:
I'll bet a bundle of snakes would look & sound awesome, but it sure would be a challenge to fit them in.
So, in fact, both engines sound very similar, with the Ferrari more raspy and cammed than the bimmer.
BTW, that's a gorgeous GTS you have. That pretty much defines the type of look I'm after if this motor goes into a Pantera body.