Truth: BFG's are identical in compound as ET streets this is why you get better hook the more rubber meets the track.
I have a set of BFG's that are at that level right now, mounted on steelies i change in 10 min. just before leaving for the track. I think the tires you have have about 3 trips to the track on them if you heat them up good before every run!!!!!! if you just lower pressure and do a quick clean off those could last a whole season.
Mine had 80% tread left when i bought them from a friend and now have about 10-20% like you, right now and i have done hard 5-8 second burns before every run and have about 30 passes on them myself.
don't bolt those on for daily use, they will be worthless in the rain and you can get ticketed for tires that bald, but for to and from the track those are perfect for a free set of DR's thank your friend alot, hell take him to Mcdonald's just to be nice.
BFG's are drag tires that are designed do well on the road
Nitto's are street tires that also double as good drag tires.
there is a reason all the competitive DR class pro's run BFG's
