Get the Opus 150w.
For one, the 12v isn't regulated. The unregulated power can and will fry your motherboard.
For two, the motherboard requires more than just 12v to operate. the motherboard is fed 12v, 5v and 3.3v from the PSU to operate properly.
For three, it's likely that the remote turn-on wire is only a pulse that's used by other devices (an amplifier for example) to initiate turn-on.