The shift from pre- to post-aspiration in the production of intervocalic /s/ + voiceless stop sequences (i.e., /pasta/, ['pah.ta] -> ['pa.tha]) has become synonymous with Andalusian Spanish in the sociophonetic literature. Adding to this, new data suggests that this change may be in early stages of development in Buenos Aires Spanish, which demonstrates variably pre- and/or post-aspirated realization of intervocalic <st> in the same contexts. Previous accounts within Articulatory Phonology (AP) (Browman & Goldstein 1986) explain the categorical shift from pre- to post-aspiration as the product of gestural phasing and extensive coarticulatory overlap (Torreira 2007a,b, Parrell 2012, Torreira 2012). A novel representational approach drawing from three theories, Q-theory (Inkelas & Shih 2013), Cue-Based Features (Pfiffner 2021), and Exemplar Theory (Johnson 1997), explains the development of these sequences as primarily the result of changing exemplar weights of the phonetic cues associated with the /s/ and /t/ segments (the coronal context being the hypothesized overall point of origin; Ruch & Peters 2016). These weights are phonologized and temporally ordered according to subsegmental q's, or feature bundles, associated with each segment, or Q. The interaction of the above frameworks offers a fruitful synchronic model, particularly in how it can account for transitional productions in which both pre- and post-aspiration are present as well as where changes in place and manner of articulation take place. The proposed account further can be used to make diachronic predictions about how /st/ has evolved, particularly whether both segments remain underlyingly, and where they might be predicted to shift in the future.