(i) I'd be inclined to get a pair of JBL 128H-1(s) from eBay, refoam them, drop them in & then give them a go .
- If they don't work out , toss them back out on the Bay .
(ii) Also ( used ) , the JBL 2203 (a or H ) . Typical refoaming advice applies .
(iii) The GPA 3124 is a contender ( if you prefer to buy new ) .
(iv) The le14a ( 14" ) could be a good choice if the box size of the M14 is over 3 cu ft ( but less than 4 )