You are not missing any success stories regarding the Hopkins Wiring Harness # HM11141824 from customers with a Miata, it is likely because the vehicle is not made for towing. I took a look at the owner's manual for a 2008 Mazda MX-5 Miata, and the trailer towing section reads "Never tow a trailer with your Mazda MX-5."
It may not seem like a particularly dangerous thing to haul a small cargo trailer, but the weight adds stress to your Miata that it was not designed to handle. This could... view full answer...
The overall weight of the Roadmaster Direct-Connect Base Plate Kit part # RM-524450-5 which is a fit for your 2016 Mazda MX-5 Miata is right at 50 lbs. If you can let me know what all components you are interested in I would be glad to give you the overall weight of each product. view full answer...