i used to own a pair of 2.9's years ago. they were on the bright side so i matched them with the macintosh ma-6500 integrated amp with the sa-3 sub amp. nice combination for a small medium room. i would only use the sa-3 amp if you have a small room so you can adjust the bass seperately. since the 2.9 need a lot of power to get them to sound their best, this doesn't work in a small room. in a small room, you can adjust the bass so you cn hear it even if you have a low volume on your preamp. if you don't want to biamp the speakers, look for the classe cap-151, macintosh ma-6900, or a used dk design mk II. any 1 of these will have the power to control the lower octaves. IMO, i would not use a 50 watt integrated with these speakers (unless you biamp with 150 watt monoblocks for the woofers), not enough power. the ma-6500 with 100 watts was not enough and i had a small room.
good luck
good luck