Regarding Bridges :
Its is an Issue that these Canals near border or separate from main roads can only take BMP weight,Those bridges cannot take more than 40tons at max, DRDO bridges will not only benefit Arjun but also those of T-90S and T-72M1 as it is not mention about as these are not DRDO made..
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Regarding Other Points :
In the link it is state clearly Arjun preform better and expected than T-90S in mobility and accuracy so does Army says the same, above that Indian Army already using Arjun in mass loge-tic chain is already made, Arjun are transported only by trains and Roads just like other MBTs, It can be also airlifted when C-17s will be operational.
In case one doubt above points, Please do ask..