Me and you both! I just got the SP200 yesterday- listened to music for hours last night through my Elear. Background definitely blacker with more space around each note- I wouldn't say the SP200 did anything to the width of the sound stage but the depth definitely sounded deeper and the placement of the notes seemed more precise. It's like putting on glasses for you music- everything is clearer! Using the XLR inputs from the dac and listening through the 3.5mm jack, I can only go to around 8:30ish on the volume knob on low gain- powerful amp!
The only thing about that amp I don't like is the volume adjustment. Just the smallest touch can make the volume go really loud. I don't even bother with IEMs but I never use them much at he anyway.
I used my Elear for a few hours today and they did sound wonderful. The background definitely was darker and the added depth was a real treat. Anyone that doesn't have a THX based amp needs to get one, your ears with thank you.