Hi! Don't expect that rolling OPs will give you a day and night difference in sound. Your Matrix M-Stage will still be a Matrix M-Stage even after the upgrade . The sound will "tighten up" a bit with a little more open high end and little better details. I have modded with an LM4562. I ordered a free sample from Texas Instruments (National Semicondustors) : http://www.ti.com/product/lm4562
Maybe you should start there.
Thank you for all your help i bought the opa627ap from tamaudio.