Ford Forum - Enthusiast Forums for Ford Owners - Should i buy a rav 2006 f350 with 6.0 liter?

Good morning everyone. I am considering purchasing a 2006 Ford F350 with the 6.0 liter diesel motor. This vehicle is a RAV which the dealership said the issues were no power at cruising speeds and black smoke. They said that all of the issues were fixed. The truck came out of California and has 92,000 miles on it.
I have done some research on the internet and have found there are some issues with the 6.0 during certain years. Is the 2006 in those problem years?
I currently own a 1999 F350 with the 7.3 and am wondering if I should keep it or upgrade to this newer unit?
Anyone with imput would be appreciated!
Thank you, Leo