U r damn right, we need medium range SAM now rather than Su-30. We need to protect our communication at any cost, ex- Jamuna Bridge, Herdinz Bridge and the Lalon shah Bridge beside the Herdinz Bridge, Gomoti Bridge, all gas field etc.
Armaments means Su-30? OK forget about the Flanker but don't u think we need modern fighter beside our MIG-29? Cuz Q-5C or A-5III and F-7MB are too old now.
I think this is time for us to make an initial project for aero space industry as Defence college has opened aeronautical engineering.
Nobody will disagree with you about the need to purchase fighter jets. But, I would suggest a little patience. Think of our geography, it is so small and it has no depth. A Su-30 still in Indian sky in Tezpur can easily target our vital institutions from there. If India builds an airbase in Tripura, the Sukhois there can target Dhaka, Chittagong, Comilla and Sylhet.
However we try we cannot match the Indian air superiority in terms of number of jets, at least not yet. So, I think, the immediate best defence should be based on SAM missiles alongwith 3D radar systems. In times of real war, India will destroy quite a number of these SAMs, no doubt. But, there still will remain many more to challenge them in the sky.
In my opinion, fixed SAM sites should be avoided, instead, SAMs should be fitted on trucks roaming anywhere and on missile boats roaming in the rivers and shallow seas. When we have a proper defense system, only then it will lighten the burden of fear from attacks by India or Burma. They will be forced to respect our sovereignty.
Cost calculation will show that SAM defense system will be much cheaper than jet fighters, but still many more times effective. At the present condition of economy, we can buy only a few squadrons of fighter planes. This costly purchase will give us only a false sense of protection, but will not cause an inch of dent to the Indian air superiority.
Therefore, I suggest SAM system now, and when the economy develops, then we go for the offensive weapons.