The pearl should definitely be an upgrade compared to the Pioneer. Your speakers are a more difficult issue, as your room is quite small. For any speaker you might choose, a home demo is a must.
You probably can't accomodate any floorstander, but I recommend you check out some of the Totem models anyway, Arro or possibly Staff. Previous Kef Q series would be happy with little space as well, I'm not sure how well the current Q500 does.
In my opinion, you're best served by unfussy standmounts. If you're not looking for deep bass (or can live without it -- I don't expect the Piega's to go very deep), I suggest you try to find a pair of Dali Mentor Menuets. The Dynaudio DM2/6 are also easy to place (according to lore, have no experience with them), and should provide more bass than the Menuets.
(edit: the last paragraph is about standmounts, not floorstanders. doh)