The McIntosh amps are pretty good but the ARC (especially their Reference line), Boulder, Luxman, Pass Labs and the D’Agostino amps are leagues ahead and big step up from McIntosh.
Ayre Ref will also sound good on your B&W 802 D3.
Another amp that will sound really good on your B&W 802 D3 will be the Naim 500 DR power amp with its partnering Naim 555 PS DR external power supply unit (psu). The Naim 500 DR amp does not have onboard power supplies. The Naim 500 DR amp + Naim 555 PS DR psu will be over your budget of $30k though. The combo will run you for around $34k total ($26k for the amp + $8k for the PSU). The Naim 500 DR power amp is a true dual monoural design amps with left & right channels are encased in completely separate chambers and are completely isolated and independent from each other. You could use two of the 555 PS DR power supply units, one for each channel but they will cost you even more and will drive up the total costs to $42k total. And besides, you said you won’t have additional rack shelf space.
But if you did have extra rack spaces I would highly recommend this Naim 500 DR amp + Naim 555 PS DR psu. This is a highly refined highly musical sounding amp. Do not get let down with its power output ratings of 140 wpc @ 8 ohms but this is a very capable amp more than capable of driving your B&W 802 D3 and this amp is stable down to very low impedance loads. The current delivery that matters. I’ve previously heard this amp driving a pair of big huge Focal Utopia Grande Evo iii speakers with ease and effortlessly. The sound was soo effortless.
Ayre Ref will also sound good on your B&W 802 D3.
Another amp that will sound really good on your B&W 802 D3 will be the Naim 500 DR power amp with its partnering Naim 555 PS DR external power supply unit (psu). The Naim 500 DR amp does not have onboard power supplies. The Naim 500 DR amp + Naim 555 PS DR psu will be over your budget of $30k though. The combo will run you for around $34k total ($26k for the amp + $8k for the PSU). The Naim 500 DR power amp is a true dual monoural design amps with left & right channels are encased in completely separate chambers and are completely isolated and independent from each other. You could use two of the 555 PS DR power supply units, one for each channel but they will cost you even more and will drive up the total costs to $42k total. And besides, you said you won’t have additional rack shelf space.
But if you did have extra rack spaces I would highly recommend this Naim 500 DR amp + Naim 555 PS DR psu. This is a highly refined highly musical sounding amp. Do not get let down with its power output ratings of 140 wpc @ 8 ohms but this is a very capable amp more than capable of driving your B&W 802 D3 and this amp is stable down to very low impedance loads. The current delivery that matters. I’ve previously heard this amp driving a pair of big huge Focal Utopia Grande Evo iii speakers with ease and effortlessly. The sound was soo effortless.