Between the two i would definitely choose the medium option as someone stated the XL is a rather large sub. Btw the tantric hd is another great sub option lolWould this enclosure from Dave the Box Guy be sufficient?
Small:
Net box volume (after port displacement and avg. sub displacement of .12ft3): 1.5ft3 net volume
Overall dimensions: 29"w x 14.5"h x 13" d
Tuning: 33hz
or
Medium:
Net box volume (after port displacement and avg. sub displacement of .12ft3): 1.85ft3 net volume
Overall dimensions: 29.5"w x 14.5"h x 14" d
Tuning: 32hz