You could do it yourself if you feel comfortable doing something like a cam swap. Shop time is like 4 hours a side.

To tell you the truth, I'm not sure what (if any) risk you are running not fixing it, I believe it is more of a performance issue.

 

I spoke with a local Ford Dealer yesterday about the cam phasers. He gave me an estimate for just over $1000 with parts and labor. The way the service manager explained it, the ticking isn't doing any real harm - but when they actually go bad, the truck gets noticeably rough, which obviously, is when you'll have to take the hit on the repair.