Very interesting! Thank you!! It reminded me the heyday of the Yugos and Renault 5GTs, just as in rallies in our country.
The history about the GTL FIA homologation is directly related to former Yugoslavia. It was the idea of the local Renault to create such an homologation, and not of Renault France, since the R4 made an ideal class in rallies (local production, robust, cheap to maintain, could be an opponent to the very strong Yugo class...).
It's interesting to read the Gr.A papers since they allow rear disc brakes, hydraulic handbrake, 5 speed gearbox, Uniball tie-rod bush among others. It was issued in 1986 and was valid until 2000. This meant, anyone could race a R4 in a WRC event until 2000.
Portuguese Pinto dos Santos was brave enough to do so, from 1998-2000. Among other rallies, he entered our Acropolis Rally in 1998 and 2000. I consider myself very lucky to see a R4 competing (sort of...) against other well-known rally cars! The remarkable fact was that this R4 was completely stock-down to its air filter and tyres (normal M+S ones!!) They didn't have any service assistant, they carried tools and spares and did the repairs themselves.
There was also French crew Cesbron/Geraud, who entered Monte Carlo rally (and various french championship rallyes too) in a R4 back in '91-'92. Their car was however prepared to full Gr.A specs (including a 70 HP 688 engine), the 4L Magazine had an article on this in some previous issue.