The Multiplex Cularis is a great 2.4m glider, but space is very tight inside. It really wasn’t meant for autopilots or FPV, which is exactly why some of us are doing it anyway 
(it does require a fair amount of work to carve the inside to make room so that the outside stays as clean and drag-free as possible).
On a day with good lift, it should be able to stay aloft for a long time without any motor power while still weighing around 2.1kg.
http://marc.merlins.org/perso/rc/post_2015-04-23_FPV-with-Multiplex-Cularis_-v2.html