Become a MacRumors Supporter for $50/year with no ads, ability to filter front page stories, and private forums.
Either will work. Why don't you get a regular Toslink cable, and then order an adapter. What length do you want? I'll find you a link for what you need.

That TOSLINK cable I linked him to comes with an adapter. Use "(2) Digital optical for DVD or CD players, PlayStation®2, Xbox™*, or PC sound cards (requires optical cable, sold separately)" to hook it up to your MBP.
 
I own these speakers. They are fantastic. I love 'em. All you need is a mini toslink cable to regular toslink and thats it.

Not only do i have the speakers, but i have the same exact cable that Garsteff posted, from monoprice. get em both and youll be happy
 
Unless you really must have the wireless rear speakers of the 5450. I would get the 5400 or 5500 instead. Both produce better sound (because the back speakers on the 5450 only do 16bit vs 24bit on the other ones).
 
I have the same set (Z-5450) and a Belkin TOSLINK cable running from my Mac mini. Runs fantastic. My advice, if you have not already purchased the system, is to poke through Froogle. I ended up getting mine brand new (sealed) off eBay for $250.
 
The z-5450 is a discontinued and inferior product. My advice is to jump for a Logitech z-5500 or Kilpsch ProMedia Ultra 5.1
 
Register on MacRumors! This sidebar will go away, and you'll see fewer ads.