M&H, M/T, Hoosier, and Nitto all make 325/50x15 tires. Are you open to bias tires, or do they have to be radials?
In my never-to-be-humble opinion, if you are looking for something that has great dragstrip and street traction, decent tire life, and safe rain traction at freeway speed, it doesn't exist. Any kind of safe rain traction will have huge water transfer voids, and can't have decent drag traction. For what you are asking, I think your best compromise would be the nittos (they claim their tread pattern for their nt555r is safe in wet or dry) the M&H drag radials,(very little void, 25 mph in rain...maybe) Or M/T street ss (more void than et street r,). Then there are always the bias tires, Hoosier quick time, and qt pro, M/T ETstreet, and M&H muscle car drag tires. Excellent race track traction, absolutely deadly in the rain.
Personal opinion...i definitely agree with those that say to get extra wheels for your strip tires, and use them on the strip only.