If the following post is correct, your speakers are actually 4ohms each. Since you are running 2 pairs of speakers, you are loading the amp with 2 Ohms. I almost can't believe this could be true because I don't think any budget to mid level receiver/amp could survive this over decades (unless you play it soft in a small room).
In any case, if you like those speakers and plan to continue running two pairs, you should definitely get an amp with four channels so you won't have to run the speakers in parallel.
Re: Are EPI 250's really 8 Ohms??? - corerosin - Vintage Asylum
The $900 XPA-5 is definitely the value leader in this category; however, the 19" depth (plus add room for plugs) can be a problem if you want to fit it into an existing shelf/wall unit.
If this is a problem, the closest thing out there I know of is is an Ati 1805 for $1100 which is 16" deep (plus plugs). This is B-stock, but several people here have ordered from them and think it is really new stock.
ATI AT1805 Rack-mount Five Channel x 180 Watt Amplifier - B-Stock (120V) - Amplifiers
Edit: I am not an Ati - Classic Audio shill. I am an idiot who ordered an Emotiva amp (UPA-5 in my case) without looking at how unusually deep the amp was (compared to my other components) and would like to save others from the same mistake!