@DJ LP
I have a burson V5i and V6 Classic, and tested with 2228, 1612, 8820, 1361, 1364, 8620, 275 and 49720.
For price/performance 2228 is best opamp and you can buy. You can use a little better 228 as 2x single configuration for xd05+
V5i will be notable superior. Quite similar in sound signature to 2228 but definitely higher level. You can go for V5i dual for better fit.
V6 Classic (don't heard vivid) is only a little better than V5i. 40% more power consumption and can't fit without heavy modifications, no protection from RFI as V5i.
V6 is made for hi-grade desktop audio equipment as upgrade stock IC and there can really do the job.