My marantz pm6005 drive Wharfedale 9.5 (less sensitive 86db) effortlessly. Bass is very good.
I recently (around an year back) purchased pre owned pm8004 which is entirely different, may be it is laid back and very descent for long listening sessions.
On the other side 6005 is very dynamic and definitely lacking the details.
So my suggestion would be save more and go for 8005 so that you can restrain from upgrade itch.
It's my opinion after an year.
monitor Audio Bronze 5 speakers has a high level of sensitivity - 90 DB . So if u are going to listen to music at moderate volumes then Marantz PM6006 should be able to drive it .... in case u have a habit of listening to music at high volumes or u have a large room ...then go for a amp in the range of 70 to 100 watts i.e Marantz PM8005 would be an option . or in case of budgetary constraints ...check out pre-owned amps or Norge amps