AMP or Preamp

You might try contacting Wilson and ask them what amps they use at shows to demo their speakers, where they'd be wanting to make a good impression. Not knowing enough to choose an amp for my Magico A3's,  I contacted a VP there and found out they were demoing these speakers at shows with Luxman 509 amps. So I figured I couldn't go too wrong with a Luxman even though I could only afford the 507 model, one step down. Did the same with the speaker cables.

The Magico company's president had recommended a Hegel integrated amp for the A3's in articles I'd read, which I'd also seriously considered. But Hegels being manufactured in China, where quality control is such an endemic issue, was too big a chance to take on a big purchase. 

Mike

Preamp.

I agree with the others that your speakers are not reaching there full potential with your current amplification. There are many good choices with different benefits. I have in general found separate amps and preamps superior. MacIntosh  offers high reliability, long tern serviceability, and good resale value. However I have not found their audio performance a good value. The suggestion to try a local dealer is likely to provide a lot of good choices

Hear the Wilson and Audio research and is good combination (tube amp).
also fans of Pass labs (solid state)
If space allow go separate for amp and pre .
Cheers 

@davekay

I would start with amps first. 2 large mono blocks and 2 mono block tubes. Once you have your base , go for a preamp that best suits your needs. A cherry on top sort of speak.

He only wants to spend $5K-$7K.  It seems that a used integrated would be the way to check all his boxes and find something worthy of those Wilsons.