By 06 they were pretty dialed in. Damn good motor and trans combo if you treat it right. Mine has 120k on it with only one repair.
But still wouldn't choose to own one that hasn't had the preventative stuff done.
Buying used is a gamble. Never know if they beat it, chipped it, didn't maintain it, etc. Mine was brand new and I don't pull with it and it get's a lot of kind highway miles and very little around town.
How long did your injectors last??