I've been bi-wiring my Canterbury for years (first SE, now GR), and yes I feel it's an improvement. Every time I drop the 2nd cable run and plug in those Acrolink jumpers I lose a bit , dynamics, and basic "jump factor". However I'll note that I've only tried biwiring with two separate cable runs versus a single run. I've not compared the same exact single cables, with one terminated for biwire versus another terminated single wire with jumpers - which would be like you having JPS reterminate your existing cables.
Tannoy recommends biwiring in their manuals, but then their toe-in suggestion is kinda wack so take that with a grain of salt.
Enjoy your awesome new GR speakers!