Death Metal & tech stuff...

I posted this a few weeks ago, but reposting in "Tech Talk" to try to get some more input:

I'll try to use the appropriate audio terms. Metal (death, grindcore, technical, progressive.) 300 BPM double-bass kicks drums, trem-picked A-tuned baritone guitars, so I think I'm looking for good transient bass. On the high side, trash and china and splash cymbals, but I want to hear each flavor of cymbal. Don't have to be towers, may scale down and do bookshelf-size and sub. Do I just get some used B&Ws? Budget, maybe $500/pair used.

I'm also thinking I may just build my next speakers, so also looking for any general input on engineering. Kind of tired of horns. I'm thinking I may want a sealed system, but open to suggestions including enclosure types, (sealed, transmission line, arrays,) baffle arrangements (MTM/D'Appolito, time/phase allignment,) drivers (#, size, brands,) x-overs (type, order,) etc. Thanks!

If I were to test such a speaker to an extreme:

Nile, Krisiun, Dying Fetus, Cryptopsy, Meshuggah, Decapitated, Strapping Young Lad, Opeth, Morbid Angel.

My current system:

Klipsch RF-3s (w/ homemade 10 lb. crossovers)
Nakamichi (some model, CD transport)
Adcom GDA-600 DAC (auction for 100 bucks)
Alesis 31 band graphic EQ
NAD C-350 Integrated (but also playing w/ Yamaha AX-500 a friend gave me.)