The T/S specs look good for OB, Qts of ~1.2 and fs in the mid 40's are a great combination, and cost is very low. But the SPL of 87 dB/W/m coupled with a 3 mm Xmax may limit you on how loud you can play the finished speakers. Two drivers per side will help. There is a reason that 15" woofers are popular for OB, higher SPL/W/m.