It depends on how often you are going to be towing a load that size and how far you're going. I have a 23' boat that weighs 4000lbs dry and after gas (60gal tank) and gear, I'm pretty sure I'm close to being at my max towing capacity on my 07 lux (specially since I have 35" tires).
It's only a few miles from where I store my boat to the river, which is a blessing, because it struggles a bit and sometimes that boat wants to tell my truck where to go, but overall it's not terrible as long as you don't mind going slow.
As far as stopping and starting, there aren't really any issues. The I5 has plenty of low end to get you going (again, not fast) and the brakes on our trucks are ridiculously good, so stopping has never been a problem. The only time I've ever really had a doubt was going uphill on a steep incline in town where I had to floor it to keep the truck at 30mph.
After talking with the dealer and some of my buddies who know about towing, I've learned that as long as I don't plan on taking my boat to a lake a few hundred miles away and I don't try to tow it every day, the truck will be fine now and in the future.
a person whose life is devoted to the pursuit of pleasure and self-gratification.