the D2 is not renowned for fantastic SQ, but a good subamp nonetheless. however, the alpine should sound nicer (if you can hear those sorts of things).
the L7 subs are superior to the alpine type-R though.
IF you were limited to only those choices, i'd go the EQ-L7 combo cos the subs (and their box) are more important than the amp. obviously ensure you build or have built a suitable subbox for the subs for SQ.