I might be slightly biased, but I'll present some facts. The fact is, the Sapphire XLs are a very easy amplifier load. Certainly they will benefit as the quality of electronics in front of them goes up. But, they can be easily driven by just about anything. During development we ran them hard on a 15 year old $120 30w/pc rec, SET amps, 300 watt mono blocks . . . . you name it. I even hooked them up to a boom box.
One time a very knowledgable and experiences manufacturer's rep was telling me that there was no way their 6 watt SET would even play through the XLs. He said it wasn't possible for a small monitor like these with a crossover. I should have bet him cash, it worked fine! Your receiver will do just fine, you can look forward to greater refinement down the road when you upgrade electronics.
They are rear ported so you will want them a little way out from the rear wall, the curtains are okay. From your photo, looked like they'd be far enough out.