i have a yamaha rx-v450 driving apair of diamond 8.4 and a diamond 8 center. can you suggest to me as to whether the diamond 8.1 or the wh-2 surround from wharfedale for surround channels. i must say the center just blew me away straight out of the box. will my receiver be able to drive all these speakers which are all 86db(sensitivity). any and all suggestions are welcome.