Moving to a vented system greatly increases the power handling around Fb, but below Fc you basically have only the suspension stiffness to limit the excursion, the port acts as a leak. I generally prefer vented systems but especially when they are large and low tuned say 20- 35 Hz.
I'd say try it, it is the only way to learn, but perhaps build a quick and dirty cabinet to try out different ideas. Also, don't be afraid to throw out the book and tune lower. You might try a cabinet twice as large as you plan tuned to 45 Hz. Low tuned vented systems tend to have an early roll off shape closer to closed box systems but with much more power handling around Fb because the port does the work and the cone displacement theoretically goes to a minimum. A double woofer MTM or MMT version in a 10 liter cabinet might be very interesting.
You might have more satisfying results experimenting with a system with an 8" or larger driver since it will generally have much more volume displacement.
