The name Extrema was used until 1995, but at the same time the model has always been called RS. Along with the Cagiva Mito 125 it has been the longest running model, updated in many respects during the years. aprilia stated that this name means "reaching the peak of the balance between the engine and frame performances" and not the extreme racing purpose.

The "extrema" often is not found on the price lists or in the documentation because it seems that aprilia used this name for the "not replica" versions and that simply called RS Replica, Sport Production, etc. the racing-look-like bikes. Most likely the choice was made to shorten the name of the model.

In practice the sticker of the frame near the pivot has the mark Extrema in a red field for 1994 to 1995 in any version. For the previous MY the decal extrema could be on thank or fairing or tail, with exception for Replicas year 1992 and 1993 and the SP 1993. In any case if the name used are R, Replica, Chesterfield, SP, sport pro or other the bikes are all RS Extrema, although there are several variations and evolutions.

The Extrema is the beginning of new era of the RS series that replaces the previous AF1 that was characterized by single-arm made in steel at the rear axle. The contact points between the two are relegated, and only in some cases, to the engine and some other components such as brake calipers, front headlight, etc.. The frame is completely new, as well as the swing arm. The mellow and liquid shapes are similar to the 250cc MotoGP including the "Banana" or "boomerang" swingarm. The racing bikes of GP championships change in the same year the mark from AF1 to RS (W, A, etc.).

The Extrema were never restricted in Italy: the last RS "full power" was sold in 1996, the only one that completely lost the mark extrema.