Tire compound formulations change all the time. Michelin is the current owner of BFG and they did a reformulation about 9-10 years ago. They are a good street tire but just can't be put in the same camp as a really high performance tire. And when it comes to 15" diameter, choices are very limited.
I've used W rated tires on my other cars. I can tell you that in my case they were a waste of money and had handling issues. They have low temperature limits and they generally suck in the wet.
My Pirelli P7's fit right in there under the "big suck" catagory.
Anyone who insists on paying for a prestige tire rating is welcome. I just seriously wonder if the new owner will even know the difference.
I'm not a BFG stock holder. I've had high performance cars since 1968. I know what works and what doesn't.
When my kids ask for my opinion I give it. Then I let them make their own choice. It doesn't matter if I'm happy with your choice. It matters if you are.