metrum octave dac or cary or wyred4sound and more

hi my friends i m read alot about this metrum dac and im consider it seriouesly.but i like to know few things :
1.i have small ion pc of fujitsu and have only toslink outpot port from my digital port of my small pc.so i like to know if its importent to consider it bcz metrum doesnt have usb in.i like to know how it will be the resault what u thinks ?

2.because the metrum is nos dac how it can play hiraz files music with good quality (is it importent) what the diffrent ?
3.i have leben amp cs600 and devore nines speakers what will be the best match for my system : metrum or cary exiter dac or wyred 4 sound dac1/2 ? what the diffrent between them what more musically and match for my system

thanks alot hope to get alot response and opnions ..
bye .