BX2 and Marantz AVRs

Hi everybody!

Need some opinions; I have MA BX2 speakers on stands in my living room with Marantz NR1602 receiver, plan to add BX center and existing KEF T101 I will put for surrounds.

For movies and PS3 I am quite happy with the system, music is also very good, but started to wonder could I get better soundstage and SQ if I upgrade to higher Marantz AVR, someting like SR5007, or even SR6007?

What do you think would I get any real improvement as BX2 are good, but are budget speakers; or would 6007 be an overkill? Thanks!!