Sub wolfer advice

Hey guys I need some advise on a power sub. Here is my set up. Krell FPB 400CX & Krell KCT pre-amp with BMW speakers. I have never run a power sub before. I will be running my transparent cables from the amp to the power sub. Then another set of cables out of the sub into my BMW's. The sub will be 2ft away from my right speaker. Do I need to keep both lengths of speaker wire coming out of the sub into my BMW's the same length or can I run a short speaker lead from the sub to my BMW speaker that is sitting next to the sub or am I splitting hairs?

Next question should the speaker wirer coming out of my amp going into the powered sub need to be the same quality of wire going into the speakers?

Thanks guys for all your help in advance. Hope this makes sense. Any help you can give will be greatly appreciated.

NO, As long as its is of good quality with appropriate shielding.
Why not go from the amp to your sub and from your amp to your speakers? (bi-wired) Much better than from the sub to the speakers.