It's worth every penny, and I seriously doubt you'll be able to retro-fit it for anything less than stupid money (£1000+) if it's even possible.
I'm not too bothered about the duel zone feature just the screen and how you can simply set it up and drive, instead of fiddling with it every 5 minutes when you get too cold/hot.
Yep Climate Control is brilliant, one of the best features of my car- I love it!