Upgrade advice needed

Over the last two years I put together my first and current system with gently used equipment which cost a total of $7,500 (two kids in college so the budget is always tight):
Marantz PM11S3 integrated amp
Marantz SA11S3 SACD player
Music Hall MMF-9.1 turntable
Dynavector 10x5 cartridge
Focal 836V tower speakers
Focal SW800v subwoofer
Acoustic Zen speaker cables and interconnects

I am considering an upgrade of the speakers to Focal Electra 1028 be towers and Focal SW1000 be subwoofer to  get the extended range these afford. I am concerned as to whether these speakers will cause me to want to then upgrade my integrated amp.  Is the Marantz a good match for these speakers (I love the Focal sound)?

I think your present system would be a good match with the 1028 be's as long as you don't have a huge room or listen very loudly.

The 1028 may want more pwr to be at there best,something you could change as your budget allows.Nothing wrong in moving up the ladder with the same brand if you like there general house Sound.

As a Marantz PM-15S2 owner myself, the great thing I have found about Marantz reference series integrateds is that they stop the dreaded upgrade spiral.  At least for me.

I would say your PMS3 would be a good match as you move up the Focal ladder to Electras. 
your amp will sound great with them, but of course you will want a better amp...