Law 41 (SEM Visa) (Panama City)

Is anyone on here in Panama on a SEM Visa under Law 41? I heard that there are benefits to having this Visa, such as buying a new car tax and/or duty free.

However, I can't seem to find any documentation that says this for certain (everything I find relates specifically to the company itself).

When going to the car dealerships, they all claim to have SEM pricing, but each one has their own interpretation of what taxes or fees you must pay, so I'm not sure if I am getting gringo prices or not.

I was ready to sign the paperwork at Nissan on Saturday until the sales guy added 7% Impuesto to the final price, even after I was originally quoted a price that didn't include it. He then said the original quote was a mistake.
He could be right, but Honda claims to not have that 7% at all (but so did Nissan until I actually went to sign). Mitsubishi had a different logic altogether.

Just hoping to be informed so I can make the right decision.

Thanks.