Thank you all for your suggestions.
So based on the price range and the appearance, I have narrowed it to the following ( in approximate order of price, low to high):
Kanto Sub 8
Jamos S 808
RSL Speedwoofer 10s MKII
Any of these that I should specifically avoid? Any of these that punch above their weight in terms of sound quality?
The speakers that I have are supposed to be "quick" and hence I was looking for 8" in the first place.