Driveshaft trouble

I replaced mine with a kit from ebay, looks just like the kit from Brewers. Mine was original from 1962, pulled the balls, removed and cleaned the needle bearings in both, packed with grease and reinstalled. I never touched the trunion bar. Like said above, it needs to be perfectly centered. No play and should be good for years to come.

For those who had the slip joint mod done, what was the part cost and labor cost to have it done?