I think Yamaha's HS80 second hand is good choice for that money and you will definitely hear the difference between consumer speakers and flat detailed monitors, even with them and some other ones, I guess you watched the video I left you about Adam ones, can you hear how good A7X are compared to other two, but imagine that two compared with some cheaper ones and whatnot, they are still better deal, so you catch my drift, you will definitely hear the difference right away.

 

I tink 8"inch is way too bass-heavy for your space. I'd go for the 6"inch or the new Yamahas (HS8). More flat.