Last year when I spoke the Hoosier rep at StL he told me not to mix 04's & 05"s on the same axel. It seems the 05's are suppose to have better grip. You may want to mix them front to rear. If car is loose put the 05's on the back and 04's on the front. If tight go the other way. I don't know if it will work or just make the care EVIL. :119: