Amp recommendation and setup advice please

fuses - fuses can change the character of the sound in your audio equipment.  The stock fuses are usually bright/harsh/tinny as they have a lot of electrical resonance.  A few fuses I would look at:  Isoclean, Furutech, PADIS.  The Isoclean are made from gold-plated copper material.  They have a nice warm sound and can help take the edge off of harsh sounding electronics.  They can rolloff some of the high frequencies in some equipment.  The Furutech fuses are completely opposite - as they are very fast and very transparent.  Very strong deep tight bass, lots of extreme clarity in the upper mids and highs.  The Furutech are rhodium plated, which can be a double-edged sword in the sense that it can reveal flaws in your equipment (such as bad power cord, poor power supply, poor circuits, etc.).  They are the highest resolution fuses, in my opinion.

The PADIS fuses are just about directly in the middle, but still significantly better than any stock fuse.  They are not so warm and slow as the Isoclean, but not as fast and high resolution/sweet as the Furutech.  They are very cheap at $25USD plus shipping.  You can get them on ebay and they are shipped from Germany.

There are other fuses - Hi Fi Tuning Supreme (which is silver -- I don't like these in audio circuits, but they are excellent in digital transports).  The Synergistic BLUE fuse has been getting very positive reviews, but they are extremely expensive.

I can't see any way to replace the fuse in the Audio-GD.  The Klipsch subwoofer uses a small 5mm x 20mm size fuses - 5A for 110V, 4A for 220V.  The Yamaha uses a small 5mm x 20mm 2.5A fuse, but you can just use a 3A.  The Yamaha fuse is inside on the circuit board, which requires you to disassemble the box.  Removing the tweeter/woofer and then taking out the plate amp is required to replace the fuse.

Please be aware that there are several naysayers and unbelievers on this forum about fuses - they have a tendency to very negatively attack any conversation about fuses -- at that point, the discussion goes into a toilet with a huge argument.  Just warning ya.

Upgraded power cords can also improve the sound of electronics.  There are tons of different opinions, but in my testing, solid-core conductors beat everything else.  The Audioquest power cords all use solid-core conductors (except for the very cheapest).  I use the NRG-4 power cord, which is the best Audioquest cord without the DBS battery.  The NRG-2 / NRG-3 / NRG-5 are also good.

The Stock NRG-4 uses gold-plated copper plugs.  The combination of solid-core PFC copper and gold-plated plugs creates a very nice natural sound with a lot of weight.  The gold-plated connectors are very warm sounding and do not have the resolution of other connectors.  I always chop the ends and put on Furutech Rhodium plugs, which is always superior in high resolution sound and deep/tight bass.  The stock Audioquest cables are very nice.  The more expensive ones use DBS battery and also use silver-plated plugs.

The Audioquest power cords can be got used on ebay (which is perfectly fine).  Just search for "audioquest nrg" and you'll get a couple from UK and many from USA.