If you decide to go with extension units be certain to research for some good solid mirrors. My keel sailboat sits high enough on the trailer that it doesn't interfere much at all with rear vision. I bought extensions to fit to my T1N when I bought our Jayco travel trailer. I find that they jump around and vibrate to the point of distraction.
How big is the trailer that you intend to tow? A short test drive might show your OEM mirrors are fine.
I gave up on the extensions because I've been fine towing with either my 2004 and 2006 OEM mirrors. The 2004 has the molded plastic arm mirrors. The 2006 has tube arm mirrors which do stick out a bit further.
Lane changing hasn't been a problem with the travel trailer. I do have a blind area behind it. I don't have that issue with the boat. A wireless camera on a travel trailer as mentioned might be worthwhile.
There are a few adjustments for the OEM mirrors.
https://sprinter-source.com/forum/showthread.php?t=48873
vic