I’m looking for an sleek integrated amp under $15k

Linn Klimax DSM.  Brand new.  If not in Europe, price is even lower after subtracting VAT.

https://www.ebay.com/itm/374690462064?hash=item573d4ab970:g:UPcAAOSw~bZj66EV&amdata=enc%3AAQAIAAAAwJgJKJkKtWTE8GZ%2BsmCvj70eK2Edgdr6dsSf%2B3ZfLSjAEki%2BZIfv8uILQFs%2F0oJm%2B2bqYACt6QZfcA4UohEkhidI1J83ETadPR09Cj%2BoowvBJ0zWDsHLgwgeWhZO0QEc%2FMTZcCzAIpx0EVqvvV0Hf%2F4ctVkihR9hv93CJvI%2BBsUQ3X7PVdHgGFOdm%2B9%2BaBVS2GXDhl%2FOzFK0bJpFNX4uPSH700DmpQ551m85xdhyJE4thJnPaDV165GQlEaeTZYIJA%3D%3D%7Ctkp%3ABk9SR-DXuOaPYw

The current crop of Mola Mola amplifiers are not old technology.  They represent up to five generations beyond even the NCore module. The outlying circuitry is also unique to Mola Mola. Regardless of class of operation, they sound fantastic! 

That is an easy one. Not becasue it 'destroys' all the competition (lot of great amps listed in this thread.) But the Vitus house sound is something special. 

The Vitus SIA-025 Mk2 or 030 if you needed a bit more power but don't let the power rating of either fool you. These are high current amps with 1.4kv trannies.

The only integrated amps I have not owned in this thread are any of the Hagel's, the 866 or the Dart. but on the other side of the pond, Vitus is king........8-10 mo production wait, nearly no product here in the USA. Rarely come up used, rarely come up in discussion.

@petland  so you like it better than the Mola Mola?

Depends on what you mean by sleek. And how musical do you want to get?  You’ve got a nice budget. If sleek means a special old school look, unparalleled craft, stunning musicality, and flexibility because of optional DAC and phono cards, look no further than Accuphase. If sleek means more modern, simple box, Naim will do the job better than most. In between as someone else suggested, Boulder.