what center to go with nht2.5i

what center to go with nht2.5i and does it need the same power as the mains are getting or is 50% ok
nht center 1 or use a single nht shielded speaker...super one..etc.
NHT Audiocenter 1 would make a good match with 2.5's - I have this in my HT setup. The Audiocenter 1's are listed here often for a decent price, around $200.
i'm currently using a polk rti38, am i going to notice the differance for the better.