As one who owned the X1 (twice), X2, TD1.2 and TD3.2 I can tell first hand the Raidho's have specific needs to make them sing. It's impossible to gauge what a Raidho will sound like with an amp using a completely different speaker. The absolute best have been the Aavik amps and, until the Borresen split, Raidho was using the U300 exclusively for their shows.
Soix is right, these speakers really like Hybrid amps. While not an integrated, the Rogue Medusa and the later Dragon were fantastic, particularly with Telefunken tubes.
The Lumin AMP was also surprisingly excellent but again not integrated.
DO NOT discount the Continuum S2. I had this in house a year ago and it was right up there, checking in just below the Aavik's. I would have happily kept it if not hell bent on an all AGD system.
What doesn't work? Traditional SS amps from highly regarded Pass Labs, Levinson, McIntosh etc. The Raidho's demand a fast/accurate amp with a non-existent noise floor, which lends itself to both Hybrid and the newest iterations of D class.