AMP + SUB for BMW 3 (F30) limo.

Hello all. I'm first time here.
My wishes: To install subwoofer in BMW F30 Limousine and adequate AMP.

Could you be so kind and hlp me with suggestions;
I have AUDISON sound system with DSP processor AP 4.9 BIT with complete loudspeaker front system. Pre-out for SUB.. is still in TRUNK.
For me is important SQ sound with enough energy(not extreme loud) whic is able to produce enought freq. throung complete freq. spectrum with low APM energy.

- Which Subwoofer (max 300W RMS with as mach as possible dB, 10")
- Which AMP for such woofer ?
- Suggested location ?
(I have possibility to instal on the left side of the trunk (aprox 15 liter, or in the bottom of the trunk 25-29 liter) ?

Just for information;
till now I foud some..
WOOFERS
.. ZAPCO ST-850 XM monoblock (D CLASS) (219 EUR)
.. JL AUDIO JX 500/1 AB CLASS monoblock (discuntinued but new) (149 EUR)
.. RAINBOW BEAT 1+ D class monoblock ( disc. but new) (119 EUR)
.. DIGITAL DESIGN CM 600 (180 EUR) new

AMPS
..Audio System HX 10 SQ (199 EUR)
.. HELIX K10 W (139 EUR)
.. Morel Primo 104 (150 EUR neu !!)
.. JL AUDIO 10W3v3 (290 EUR ?)

Thank you. It will be very helpfull for me. I really don't have a lot of expiriences on this area

Kind regards
Andrej