I went with a 5' HD cable. Running any kind of Headers will make it extremely difficult to run the cable the way B&M shows it on their installation instructions. I ran mine across the top of the transmission to the passenger side, then back across the front of the bellhousing to the linkage, as shown below.
(not my car, I'm running a dust shield)
Be sure to buy a heat sheath to run the cable in, as you'll still be pretty close to your Headers and it's better to be safe than sorry (ask me how I know).
It could be a pain to run and adjust, so be patient and don't ever force it.