Intergrated

Hegel H390 or H400.

DarTZeel LHC-208 integrated- pricey but amazing.

I have an excellent condition and sounding Exposure 3010s2d in black with factory remove, box and power cord. This was the model that went from the passive preamp stage to non-passive, which was a very notable signal path upgrade. Many very positive reviews, including high class ratings.  Amazing PRAT, many say better done than Naim...

If you are going to stay with the speakers, I would opt for which amp outputs the most current at the 4-ohm ratings. I don’t know if they dip much below that at lower frequencies. I had the 509Z and absolutely loved the amp. Luxman rates the 507Z at 210wpc at 4 ohms. Even though they are outstanding amps, over time I do not know how well it will stand up to the 4-ohm spec. Contact Luxman and ask what they think. If they say it’s fine then I can promise you will not be disappointed with the 507Z.

edit: or go with the Hegel H390 or H590 and never worry about that potential issue again. 

If you heard of the excellent Vitus  brand his son 

Alluxity audio. Exceptional  integrated  amplifier  much better  then anything in 

its $11k price class  , check out the  Reviews