This paper provides evidence that, while exceptional, native-like mastery of target language phonetic properties is possible in L2 acquisition. Moreover, when multiple parameters must be learned, the relative difficulty of acquisition can be predicted based on the variability characterizing each of the properties in question; specifically, the greater the degree of variability, the more difficult a phonetic parameter will be to acquire. The data to be discussed come from a reading task that elicited Spanish stop-liquid clusters from 10 adult native speakers of English. Such clusters differ in the learners' L1 and target language as concerns stop voicing, rhotic manner, and the presence of cluster-medial epenthetic vowels in Spanish rhotic clusters. Acoustic analysis of the data reveals that stop voicing was acquired by both intermediate and advanced learners. In contrast, learners were less accurate with the rhotic, which was generally too long and often devoiced. The epenthesis pattern was even more problematic, with some intermediate learners failing to epenthesize at all and most learners producing insufficiently long vowels. Nonetheless, the production of one of the ten learners was statistically indistinguishable from four of the ten native speaker controls as concerns all three phonetic properties.