January 2016 reports from Russia are that Russian AIP (essential to market Amurs) has not been developed hence additional Ladas and any export Amurs will no longer be built. In December 2015 or Janaury 2016 it is likely that Russia offered Morocco the Improved Kilo class instead. This is assuming Morocco would not accept a Russian offer of a future "fifth generation" Kalina class SSK - with the Kalinas only likely to be operational (with AIP) in the Russian Navy in the mid 2020s.
Saudi Arabia may well be paying the upfront price for Morocco's future Amur 1650 but Morocco might be surprised how high the downstream maintenance, spare parts and crew costs will be.
http://www.moroccoworldnews.com/2015/08/166436/saudi-arabia-to-pay-for-submarine-morocco-will-buy-from-russia-source mentions that Russian-Algerian relations are frosty due to their divergent positions with regard to the energy strategy of the European Union.
The Amur (Russian 4th Generation SSK) is a development of Russia's 3rd Generation SSKs - the Kilos and Improved Kilos. See Russia's-Rubin's five SSK Generations concept at http://gentleseas.blogspot.com.au/2014/04/russian-conventional-submarine.html .
Russia has been attempting to sell the Amur conventional submarines for years. The never built Amurs (smaller 950, larger 1650) might be seen as export versions of the Lada class (1 completed so far) built for the Russian Navy. A weak point of the Amur-Lada has been the under-developed or non-existent air independent propulsion (AIP) system. Either Russia has had difficulty developing AIP or Russia is satisfied with nuclear propulsion (which could be seen as “super AIP”) for its own navy.
Nicky has provided some useful Youtubes concerning the Amurs - https://www.youtube.com/watch?v=CjewVnYqziU and https://www.youtube.com/watch?v=CjewVnYqziU . The Youtubes mention the Amurs' diesel-electric propulsion. As well as doing extensive engine development themselves the Russians would draw hardware testing and reverse engineering opportunities from Western marine engines sold to Russia. Russia's efficient technical intelligence gathering system would also help.