Ok, Sub is installed.
I have bought rear deck from ebay.
I had to cut a hole for 10 inch sub. And used MDF board to fit the sub there
This is how it looks
Sound is a lot better compared to sub box in the boot. Bass is clear and loud.
I have not applied any sound deadening in the boot yet, and there is minor rattling.
Alpine PDX 1.1000 is ideal if you have MS-8 / bit one or anything which can control the chracteristics of the bass. On Alpine amp, there is no bass boost or any other features, which makes it hard to integrate into system without DSP. I guess they have designed this amp to go with alpine HUs which can control the chracteristics of bass and sub volume.