"I relized that a DAC will increase sound stage, dynamics, and transparency, but is it worth the 2000 dollars"
Nobody can answer this question but you. Benchmark DAC runs around $1000 and is good. Bel Canto DAC2 is, according to Stereophile, better - fuller, more organic but is it worth extra $1000? - again you have to answer. There are some decent DACs around $500 that might be good enough for you. Computer sound card cannot be as good as good DAC, in my opinion, but again might be good enough for you. You have to try. Benchamark has free lease (direct) for 30 days and I'm pretty sure similar can be arranged with Bel Canto or dealer. Try different cables as well.
Brighter sound is not bad (compare to dull sound) as long as it's not too bright.
Nobody can answer this question but you. Benchmark DAC runs around $1000 and is good. Bel Canto DAC2 is, according to Stereophile, better - fuller, more organic but is it worth extra $1000? - again you have to answer. There are some decent DACs around $500 that might be good enough for you. Computer sound card cannot be as good as good DAC, in my opinion, but again might be good enough for you. You have to try. Benchamark has free lease (direct) for 30 days and I'm pretty sure similar can be arranged with Bel Canto or dealer. Try different cables as well.
Brighter sound is not bad (compare to dull sound) as long as it's not too bright.