Hi Maineman,
Yes, at 55 W x 5, your Onkyo 474 will have ample power to drive the VP150 center channel and your M3ti's to satisfying levels--so long as you don't expect reference levels. By reference, I mean subjectively "very loud". If you have the el cheapo (but good) Radio Shack SPL meter, don't try and push volume past 95-96 dB SPL peaks from your listening position.
And next time you have a party, don't forget this and "crank" it up. Many users with modest amps do this, drive their receivers into clipping and burn out drivers.
Regards,
