Lowthers are more horn cabinet oriented and are expensive. I say, if you want to plunge into OB world without much outlay, try some vintage 8" drivers such as the Lafayettes or even Altecs...I have my Altec 755Es in a small OB. Mighty good, but lets say lite low end, but my present standard.
I think as many out there, you are into the first time experimentation, thus, I believe that you need to get into it without too much invested.
The Hawthorne audio drivers seem like an excellent bargain for what they offer.