Presumably you mean a 3000cc (3 liter) engine?
I know you are hoping for a simple yes or no answer, but no one will give you one (or at least probably shouldn't) because it depends on too many things. Please review this Towing Rigs section in some detail, and you will probably get the answer that is right for you.
The Highlander has received a lot of discussion on this board. See for example
http://www.trailmanorowners.com/yabb...11597#msg11597
For a more generalized approach to the question, please review the entire thread at
http://www.trailmanorowners.com/yabb...10692#msg10692
There should be more than enough information in these areas to tell you how to make your decision.
Bill