Extension cab for TC combo?

Hey guys!
I have a few quick questions.

I am probably gonna need and extension cabinet for my TC BG250-208 within a few weeks.

My budget is quite limited, but I want something that matches the looks of the combo, and so I am considering one of the following TC cabs:
BC-208
K-115
K-210

The combo has plenty of mid range and a fair amount of high end, but I need more loudness and more low end punch.
The question is: which of the two K-cabs would compliment the 8" drivers of the combo the best?

Unfortunately I have no way of trying the cabinents out before buying, so any input or advice would be highly appreciated

While the BC-208 is nicely light weight, I fear that it's gonna lack low end and maybe it won't be loud enough either. Does anyone here have any experience with that cabinet?