TRD stuff is the Toyota aftermarket, basically accessories, so they should not affect the tow hitch location, especially muffler wise (assuming they used the stock hanger locations).
If the rear bumper looks like this, you have the factory ground effects.
If the rear bumper looks like this, you do NOT have the factory ground effects.
NOTE: The only difference is that portion of the rear bumper that hangs down between the main bumper cover with clips.
Now, if the bumper looks different than the above, then you likely have an aftermarket bumper and/or rear bumper lip - that case, you'll have to do some modifications to get the hitch to fit.