When it comes to S-300 I would like to know if this system was offered to non-Warsaw Pact nations before disintegrations of the USSR. In late 80s Soviets offered to export pratically same items to Warsaw Pact as to other countries with hard currency including Su-24, T-72S (export of soviet T-72B), etc. but S-300 was exception (together with Tochka and Oka ballistic missiles).

And something from central european late history. During Meciar regime in Slovakia, which inherited one S-300PMU battery, Slovakia wanted to gain one battery of S-300PMU-1 (Slovak army demands at that time actually called for three S-300 batteries). The deal for S-300PMU-1 was signed but only shortly before fall of Meciar and his "democracy with boxing-gloves" and new government terminated that deal.