for that room size I'd definitely go for bookshelves, rather big and high performing ones, with relatively small drivers that are fast so they dont pollute, and that can be adapted, tuned to your room and/or liking using back switch and bass plugs. No need to go second hand at that price, just get the XTZ Divine Delta brand new and prepare to learn that real high end performance is available at more reasonable prices. I own several speakers, some costing $35,000, and I also own several XTZ speakers.... My other choice would be Tannoy Legacy Cheviot for an extemely energetic, lively, musical sound. All these will pair perfectly with your Plinius.