So if we planned to for Amur which one would India choose, Amur 950 or 1650? and what do you mean by "for amur950 30 days only"? i didn't get it
Let me try to help. The Amur class is build in 2 varients, the smaller 950 and the bigger 1650. The 950 offers less performance, because the size limitation reduces the number of torpedo tubes, ammo, food or fuel that can be carried, just like less crew compartments will be available. However, it was designed with VLS for cruise missiles from the start, to provide it credible firepower. According to the Rubin (manufacturer) website, another hull modul can be added for an AIP propulsion section.
For IN, only the Amur 1650 is on offer, most likely because the 950 doesn't fullfil several requirements, like range and a endurcance, possibly number of torpedo tubes as well. This version is far bigger, even in it's basic version, which neither has a VLS or AIP section (see sub 1 below).
However, according to the manufacturer another modul can be added for the AIP section (sub 2). For cruise missile attack, nothing is mentioned about VLS at all, which would require the a 2nd modul (sub 3), infact it states:
The boat is distinguished by the capability of firing up to 6 missiles in a salvo against targets at sea and on shore
ЦÐÐ ÐТ Ð*Ñбин: Amur 1650
Which clearly hints on using torpedo tubes to launch them, this will be even confirmed in the brochure:
http://www.ckb-rubin.ru/fileadmin/editor/listovki/Amur_1650_eng.pdf
The 950 with VLS and an even an additional modul for AIP, would roughly be the size of the basic 1650, while the bigger one obviously offers only the possibility to add 1 more modul. Similar was stated by DCNS officials about Scorpene as well, when asked about the addition of Brahmos. So both, Amur 1650 and Scorpene offers Anti ship or land attack missiles only via torpedo tubes, but to similar ranges like Brahmos.
The Russians offer to integrate Brahmos only as a goody for us, because they know that Indians love it. The downside is lower performance of the sub (less endurance and range, noisier propulsion) and as even the Russian officials stated, IN never had requested the addition of Brahmos to Amur class!