After a small sub (maybe 8 or 10 inch), cheapish, but most importantly relatively low profile (15cm or less) and easily removed. Want to be able to velcro it in sideways at edge of boot of 4 door hatch. Not into big boomy bass, just enough to fill out the sound naturally with no distinct thud. Head unit has a regular aux out to feed signal to it. Somewhat tempted by Kenwood KSC-SW01 i don't necessarily want an all-in-one though.
Suggestions from the petrolheads please?