Almost forgot how awesome the Boss MT-2 Metal Zone is for bass.
Cut the Highs slightly, boost the Lows slightly, as well as boosting some lower-ish Mids a bit, on the pedal, blend it with a bit a parallel clean signal, at an about 40/60 clean/dirty ratio, and stack it all into a lower-ish gain overdrive with a grindy character, and it sounds pretty damn amazing.
I just swapped my Mosky Black Rat, that I ran in Turbo RAT, out with the Metal Zone, cause the RAT, although sounding awesome, got a bit too muddy with too much loss of definition.
Now the Turbo RAT definitely sounds more doomy, dirty and gritty, and the Metal Zone, somewhat smoother, and more power metal-ish, but at least you can hear clearly what you play, and still pretty hefty.