Exicon lateral MOSFETs are aimed at high-end hi-fi amplifiers, as they can be naturally biased towards the A region of a class AB amplifier for exceptional audio performance.
The STD03N and STD03P Darlington transistors are another good choice. Both feature built-in temperature compensation for the bias circuit, which reduces distortion and prevents thermal runaway.
The Engine 400 is a great Class D solution for hi-fi, delivering up to 400W in a compact module that still allows the designer to optimise sound characteristics with the filter and power supply design.
Also be sure to check out the input selectors and electronic volume controls.