While I'm a bit skeptical on the actual gains for a NA engine (it would be bad engineering if the TB was a bottleneck) ... port & polish sure doesn't hurt and is worth spending a few hours playing under the hood of your Jeep (I look at it more of a "fun" mod that is likely to have performance benefits as well).
Stay away from TB spacers though. That's a waste of money.
Edit: I think AJ ported his TB and liked the results...