Neither are better or worse than the others only different to be truthful. The E305 has the same chassis style/size as the old KHT2005 speaker with a vastly improved Uni-Q driver array whereas the T-305 use a conventional speaker configuration (tweeter (mounted outside of the mid-range driver), mid-range driver and woofer) remastered in a non conventional arrangement to reduce it depth.
I would say the performance of the e305 is closer to the t105 on merit with the T305 having a little more ability when mounted on the walls. If you are going to use the t305 stands, then the e305 would come out on top (in my opinion) due to the internal crossovers built into the t-series stands
The room size of 3.5m x 7m is quite a long narrow room and had you had a room which was 5m x 7m I would have said that both would have struggled at highish volumes whereas the
T305 should come out on top again. Do make sure you do buy an amplifier which can drive the speakers well in this type of room too. So, please don't look at the cheapest option as you will find that you will not be able to fill the room without overstretching the amp which in turn could cause long term issues with the speakers.
As an amp, this would be the bottom end product I would be looking at (
Marantz NR1710)