Outer Limits 4x4 Board

anyone out there changed the stock sierra driveshafts to bigger Hilux driveshafts with Double cardain Joints. is it hard/expensive to do. any other ideas on "beefing" up the stock sierra driveshafts and adding double carden joints?

i run a front hilux double cardon shaft on the rear of my zook.

there is 1mm difference in the locator so i machined a spacer to suit...