Here's a reasonable option you might consider,
The new Rega Elicit. It's 85wpc into 8 ohms and about 140 into 4.
I've had one in for review and it drives the Spires just fine!
Not sure what they cost there, but if you have a chance to try one,
see what you think. They are $3000 US and amazingly good.
Plenty of inputs and a variable output if you want to add a subwoofer
later, but if you have a small room, you probably won't need one.
Good luck on the search!