Not at all.I am reaching the end of my trucks included toyotacare services. I was changing the oil myself at 5,000 miles just because I do some short trips and some towing especially towing a camper in the summers. So I have done my own oil change between the 10,000 mile interval they do them at and was using the recommended 0w20 in the 3.5L v6.
I noticed a few things the oil is pretty darn thin. much thinner than the 5w40 my Liberty CRD took. I see the owner's manual says 5w20 is ok if 0w20 is not available. they however state that they want you to change it after 5,000 miles back to 0w20. As I have been looking at what the stores now have on the self 5w20 seems to be more often in stock than 0w20. At my local wally world every time I have went down the oil isle it's pretty sparse. I have no problem using SuperTech as it seems to meet the specs from Toyota and it will be changed regularly.
Is there any issue or any harm that could come if I switch over permanently to 5w20 or even 5w30? I would still keep with a full synthetic oil and quality filter, most likely an OEM filter. Is this 0w20 stuff just for EPA fuel conservation and will it even make a lick of difference? I'm in Pennsylvania and we do see all kinds of temperatures all year but nothing below 0F too often.
You need to understand that 20W oils are suggested by the OEM for only one reason - CAFE (corporate average fuel economy) compliance, which gets them more brownie points from the government. An extra 1/8 of a MPG per model adds up to help their fleet fuel economy average look better to the feds.
Most Toyota owners' manuals have some verbiage that allows some leeway to go with a thicker oil if your vehicle sees severe use, just as you've described (towing, etc). And believe me, the engineers would never spec a 20W if they were in charge of oil recommendations.
As a 15-year Tacoma owner, I say use a thicker grade with confidence.
You can see in my sig what we use.