Driveshaft to eliminate vibration

Okay I'm searching for a driveshaft to eliminate the typical vibration 80mph+ (I have stock steel driveshaft)

My question is;

I have a viper spec T56 and my current steel driveshaft has a yoke which was came with transmission. So what should I do? Should I order a driveshaft with a yoke who will fit my viper spec trans?? Or should I swap after I got the driveshaft? But it will affect the balance of it right? I get lost here.

I mean I should tell the driveshaft company that I need a slip yoke that will work with the 30 spline Viper shaft right? So they will bolt it and get them balanced together or what?

Balance them together; just order the whole package.

Denny's Driveshaft; best ones out there.

And what do you say for this? http://web.camaross.com/forums/showthread.php?t=538756