2 Requests

2) Watchtower
Definitely. I'd recommend "Control And Resistance".

Other recommendations with regard to request no. 2:

Sieges Even - "Life Cycle" (in the vein of Watchtower)
Sieges Even - "Steps" (less metal, maybe even more complex than "Life Cycle")
Voivod - "Nothingface"
Atrox - "Orgasm"

Also try:
Helstar - "A Distant Thunder"
Coroner - "Punishment For Decadence"
Hades - "Resisting Success" (especially the bass-solo on "Masque Of The Red Death")
Flotsam & Jetsam - "Doomsday For The Deceiver"

Not really metal, but lots of bass:
Primus - "Frizzle Fry", "Suck On This"

Definitely not metal:
Mari Boine - "eallin" (especially the bass solo on "modjás katrin") - not sure if you'll like the music, though

np: Mari Boine - "modjás katrin" (live)